You could put ascorbic acid in a sock and run it across the bottom.  The problem is that chlorine will destroy ascorbic acid and that is why I suggest dropping the chlorine level to zero.  The vitamin C tablet is useful to determine if the treatment, will work.  If the whole bottom and/or walls are stained, the sock trick may prove difficult.  I would lower the pH to about 6.8, discharge all the chlorine by adding chlorine neutralizer and then follow with ascorbic acid, using the label dosage recommendations.  If you can't find ascorbic acid, you could try using oxalic acid, but most people prefer the non-toxic ascorbic acid.  Once the stains are removed, add a double-triple dose of a quality metal treatment.  This is important to help avoid a recurrence.  Have your tap water tested.  If iron is present, add a dose of metal treatment monthly and prior to any new water being added. There is a another solution:  the METALTRAP filter physically removes iron, from the pool, as the water is recirculated through the Metal Trap.  Using the METALTRAP, to treat all new water, helps keep new additions of iron and other metals out and minimizes the possibility of staining.  Liquid METALTRAP and METALTRAP Stain Remover should be used, in conjunction with the METALTRAP filter to first remove any stains from the underwater surfaces and, finally, to remove the metals from the pool.  These product do not contain phosphates or use toxic oxalic acid.  I'm glad the you found the website.  Enjoy the season.

Sincerely.  Alan Schuster, 6/10/2008

► Ascorbic Acid Effect On Chlorine?

My pH at this point is only slightly low.  What I'm concerned about now is I used the pool today and tested after use and there is a VERY low chlorine level.  How can that be? I just shocked the pool 2 days ago.  I just put 2 tablets in the skimmer and am letting the pool run now. The water is clear and blue. (I also have a large delta UV light connected to this pool.).  But I'm just shocked that the chlorine level went down so fast. Maybe consuming all the algae really depleted the chlorine?  Or, do you think my using the ascorbic acid used for the step stains effected the chlorine level?

Pat T., 4/10/2007

Ascorbic Acid reacts with chlorine.  That is why you want the chlorine level low to before addition.  After the stains are removed and metal treatment has been added, you must keep adding chlorine, until a stable 1-3 PPM level is established.  Enough fast dissolving chlorine has to be added to destroy both the residual ascorbic acid and any remnants of algae or organic waste.  Once this is done, it should be easier to maintain.  I hope the information is helpful.

Sincerely.  Alan Schuster, 4/11/2007

Hey Alan.  Far and away, yours is the best site I have seen on stain removal. I have looked through all of the suggestions and I am hoping you will clarify a couple of things for me.  I have reddish-brown stains that are all in the area of where leaves deposited themselves, so I am 90% sure they are stains of the tannin variety.  I have read where you suggested a chlorine ratio of 5 ppm to get rid of the stains.  The thing is that I have a salt chlorinator for my gunite / plaster pool that keeps the level pretty steady between 4 and 5 parts per million depending on the temperature.  I have no algae problems, the water is crystal clear, and all chlorine is free.  The problem is that the stains aren't even close to disappearing.  My pH has been difficult to steady, but has been about 7.4 for the last week. The local pool specialist suggested that I use ascorbic acid to remove the stains, but that seems contrary to your advice.  In fact, the pool specialist explained that I had to drop my Chlorine level in order for the ascorbic acid to be effective.  Metal and mineral tests proved negative.  Should I try the pH down in the sock trick or shock the pool with tablets to increase my chlorine level?  Thanks.

The evidence does point towards tannins, but the elevated free chlorine should have done the job.  The only explanation would be poor circulation, such as if there was no main drain.  Do you have a pool cleaner?  Use it to improve the bottom circulation!  Try sprinkling some trichlor granules on the stains and leave overnight.  If this doesn't work, the problem is not tannins!  A metal stain becomes the most likely cause of the problem.  By all means try the pH reducer in a sock.  If it doesn't work, try placing a few vitamin C tablets on a stain.  If that works, then the use of ascorbic acid should be the next step.  You will have to lower the pH and zero out the chlorine level, in order to prevent the chlorine from destroying the ascorbic acid.  Once the stains are gone, add 2-3 doses of a quality metal treatment.  Allow to recirculate for 6-8 hours before storing the pH and chlorine levels.  BTW.  There is a new Solar-Powered, Robotic Pool Skimmer and should be a great help, in controlling the problem with the leaves.  It even functions, as a trichlor feeder.  Good luck and I hope that the information proves helpful.

Sincerely.  Alan Schuster, 2/23/2008

Bert S., 10/27/2008

Acorns and many types of leaves, such as live oaks or black olive, are more likely to cause staining problems.  The acorns, leaves and plant debris, remaining in prolonged contact, can release tannins and result in tea-colored stains.  The good news is that tannins are destroyed by chlorine.  All that should be required is a shock treatment and some bottom circulation.  Ascorbic acid was not a viable solution, for this problem, as it should only be used to remove stains caused by copper, iron, manganese or other heavy metals.    Poor bottom circulation, may lead to a lower chlorine level across the lower part of the pool.  Using a robotic pool cleaner on a regular basis will help improve the circulation and remove the leaves that might lead to staining.  Weak overall circulation and dead spots can add to this type of problem.  THE CIRCULATOR is a device that greatly improves circulation.  It installs in the return fitting quite easily.  I hope that this information will prove useful.

Sincerely.  Alan Schuster. 10/27/2008

► Yellow Staining After Salt Addition?

We have a 16 x 32 inground pool with a "SALT" system.  We have had to add salt in November and December and on both occasions once the salt was dispensed it has left a discolored stain in the area where the salt was poured.   The color is not black but  a light brown.  The company where we purchased the pool has been of minimal help.  If you have the slightest bit of information please let us know as this pool is only 5 months old and I am trying to save the liner.  Thanks.

Sincerely.  Alan Schuster, 12/31/2004

► Where Did The Copper Come From?

I have a 14,000 plaster pool with a heater and was recently troubled with some discoloration.  The dealer found 1.3 PPM of Copper.  I never used a copper algaecide. So where did the copper come from?  Please help.  Thanks.

Larry P., Clearwater, FL, 2/4/2003

It would appear that you have dissolved some of the copper heater core.  This is a result of low pH conditions over an extended period and can be confirmed with a Copper Test.  If your pH is too low, you must add something to the water before raising the pH.  Add a double dose of a quality Mineral Control Product and recirculate for a few hours before raising the pH or total alkalinity.  This product should complex (chelate) the copper and avoid further problems.  If you are using TriChlor tablets there is a tendency for the pH to drop over time.  Test the pH several times weekly, at the very least.  If you have an inline chlorinator, make sure that it is located after the heater and filter - NEVER BEFORE!  I hope that I have been helpful.

Sincerely.  Alan Schuster, 2/4/2003

I have a stain around my vinyl pool.   Can I use scouring powder on it to get out the borderline stain?  Is this true or will this destroy the liner?  What are your thoughts on this?  Sincerely.

Michele, 8/6/2006

The pattern on a vinyl liner is only printed on.  If you use something like scoring powder, you could remove the pattern along with the stain.  Abrasive cleaners are never recommended for use on vinyl liners!  Your best option would be to use BorderLines.  This product will allow you to apply a new border, right over the old pattern.  I hope that this information will prove to be useful.

Sincerely.  Alan Schuster, 8/72006

 

► Tan & Brown Stains?

We have a 5000 gal fiberglass pool with heater, that slowly develops stains (brown or tan) on walls, pH 7.4, TA 120. These stains can easily be removed by a stain remover (concentrated ascorbic acid), together with a metal treatment. After treatment, pump is run for 12 hours then filter is backwashed and new DE added. We treat this problem when it becomes unsightly, approx every 6 weeks.  Are you aware of any chemical/product that could be added on a continuing basis that would prevent this staining. It would be nice to have pool walls clean all the time. Could corrosion from heater be causing problem? Any other possible cause of problem? Thank you.

Sincerely.  Alan Schuster, 3/22/2004

► Gray-Black Staining?

Wonderful website!  I am desperate. We have a 4 yr old gunite pool (16,000 Gal) we inherited when we bought the house 1 year ago. The pool has a cartridge filter and a heater. Although we don't use the pool in winter, we have it maintained just like in summer, so we could swim at any time, if we wanted to heat up the water (but we haven't this year). We have been using a pool company to clean and treat the water.  We are on their regular stain treatment program.  Never had any stain problems.  Until this winter.  First it started in the area near the drains in the middle of the pool, a big dark grayish/black area developed.  Now within 2 months almost the whole pool is covered with the gray black stuff.  I tried your pH minus in the sock trick - it worked. So I had the pool guys give me 10 more pounds of the stuff and started at 7 am this morning with the tube sock, trying to move it around the pool. The pH minus is dissolving very quickly, when I move it around on the pool brush with a tube sock. By now the whole pH of the pool is at or below 6.8 and all the pH minus is gone but probably around 2/3 of the pool is still stained.  How should I proceed? Any ideas why all of the sudden the pool would start staining like this and the stain spreading over the months?  We are in Houston, Texas and we have lots of pines around us and lots of wax myrtles. We do have an automatic cleaner and clean the skimmers and scrub the pool 2x a week.  Water was filled up 4 inches 3x times last summer with no immediate effects on the staining. Thanks in advance for your help.

Marita S., Houston, TX, 2/17/2005

The problem could be caused by something in the water:  iron, copper, manganese.  Have the water tested.  You may have subjected the heater to the corrosive effects of chlorine and low pH.  If the acid made a difference, the problem is not algae or something due to the trees.  At least not entirely.  Tree stains and algae are best removed by shocking.  Mineral stains will not come off with chlorine!  I suggest you place some vitamin C tablets on a stain and allow to dissolve.  If this works, allow the pool's chlorine level to bottom out.   Drop the pH to about 6.8 and bypass the filter, if possible.  Add 2 pounds of ascorbic acid and recirculate the water.  Brush frequently.  Add a double dose of a quality metal treatment and wait 24 hours before raising the pH or adding chlorine.  It sounds like the problem was too big for the sock treatment.  Let me know how it turns out.  Good luck!

Sincerely.  Alan Schuster, 2/17/2005

I just stopped after 10 solid hours and 23 pounds of pH minus. I have not run the pump at all today, since there is no way to bypass heater and filters.  My pH test kit only goes as low as 6.8, but it is much lighter than that colour, so I assume the pH is way down.  After I emailed you, I used another 10 pounds of pH minus in the sock and kept spreading it around, but the stuff really only came off immediately underneath the sock this morning.  I have also scrubbed my heart out, and it appears overall that probably 3/4 of the staining is gone or has lightened up, which leaves me with light shadings of gray in some areas.  The pool guy only left me a pint of metal product.  I had asked him for 3.  So I went ahead and used the one pint I had, since I am worried about the dissolved stuff resettling.  I was thinking of leaving the pH low until tomorrow PM and adding some more metal product in the morning and scrubbing again really well.  I won't run the equipment until the pH is rebalanced.  Do you think this will damage the plaster?  It is already kinda worn off on all the corners by the pool cleaner and I had to patch 4 spots where the gunite was showing!  We did have some green algae early this summer and it does appear that the very first black/gray stain (1ft diameter by the drain) appeared within a few weeks after the algae were gone. It seems like it disappeared after that so.  Could the algae treatment the pool people used have caused this and, if yes, how could that have been avoided? And if it did, why would it keep spreading gray/black stuff for months after?  And why is that chelated metal treatment they are using monthly for iron, copper, manganese etc not working?  I know, lots of questions, but I am a pool novice and so tired and frustrated I am about ready to fill the thing with dirt and plant flowers!  Thank you so much for your support and I have referred your web page to our pool guys! 

Marita S., 2/18/2005

It is not algae.  Algae wouldn't come off with acid.  Yes, the acid will etch the surface a bit.  Try and keep the chlorine level low, as long as the pH is under 7.0, in order to help protect the heater.  The overall acidic conditions should even out the appearance.  If some spots remain, try locating a stain treating accessory and use it to siphon an acidic solution onto any remaining stains.  I can't comment on why the products didn't work, as I have no information relative to their content.  Possibly enough product was not added.  It is possible that the algae treatment caused the start of the problem.  Copper can stain masonry surfaces, especially in the presence of high levels of calcium hardness.  Adding some metal control product, after the algae is gone, can help minimize the possibility of staining.  Good luck.

Alan Schuster, 2/18/2005

Boy, Alan!  Do we have a sparkling pool this morning!  The pool guy just came by and couldn't believe the change either!  Your help REALLY is appreciated, recommended your website to everyone I know has a pool. Thanks a million.

Marita S., 2/19/2005

I guess it doesn't get much better that this.  Just make sure that you add a dose of a metal treatment monthly and prior to adding an makeup water.  If you use algaecide, try a polymer based product.  Glad that it all worked out.

Regards,  Alan, 2/20/2005

► Grayish Spots In Fiberglass Pool?

I have a 18 by 36 fiberglass in ground pool, and I have noticed lately that there is round grayish black spots all over the bottom, I tried scrubbing them off, but nothing, I have shocked it and put in algaecide and nothing happens, what can I do to get rid of these.  We use well water, but it is considered to be of good quality.

Robin M., 8/29/2008

The stains could be due to a metal in the water:  possibly iron and/or copper.  Cobalt can be a problem with older fiberglass pools.  If the problem turns out to be cobalt, there are products to try.  However, they may not work and the only recourse might be a refinishing.  Newer fiberglass products seem not be affected to the same extent, as older technology finishes. Try this and, hopefully, it will remove the colored spots and stains.  Add 1/2 pound of pH reducer powder to a white sock, shut off the filter and drop onto a stain.  Position using the vacuum pole and leave in place for about 15 minutes.  Move the sock around with the vacuum pole after this period.  If the stain is gone, repeat elsewhere, as needed.  Once the stains are gone, add a dose of metal treatment, in order to avoid a recurrence.  If not try the same technique using ascorbic acid - some pool dealer carry the product.  Try placing a few vitamin C tablets on the spots.  If this works it indicates that ascorbic acid will work and that it is a metal stain.  Fiberglass has a negative electrical charge and can attract positively charged metallic ions, causing the development of a stain.  The problem can be solved more effectively, with The METALTRAP Filter.  This cartridge-like filter is used to recirculate the pool water and, as water passes through its special media, metals are permanently removed.  If you use it to treat all new water and seasonally, thereafter, you should be able to better maintain the pool's appearance.  I hope that I have been helpful.

Sincerely.  Alan Schuster, 8/29/2008

► Black Spots?

First of all the basics: 22,000 vinyl liner pool with skimmer and main drain, Chlorine treated Sand filtration.  The pool gets black mud looking spots.  They can easily be brushed away, but return. I usually use a copper based algaecide. It has given some relief in the past but seems ineffective now. We keep our pool open year round but only swim in summer, we live in Atlanta.  Have you got any ideas?  Sincerely.

Mike G., Atlanta, GA, 3/10/2004

My best guess is that it is not black algae:  this type of algae is very difficult to remove and will not simply brush away.  It is possible that copper can cause some black stains, especially if the pool water is high in calcium hardness, although this is unusual with the proper use of a chelated copper algaecide.  I suggest that you discontinue use of the copper algaecide and start using another type, inasmuch as you stated that it seems not be effective.  My choice would a polymer algaecide.  It is more expensive, but worth the price.  Try this on the stains.  Put 1/2 pound of pH reducer in an old white sock, drop onto a spot.  Leave in place for a few minutes and move around with a vacuum pole.  If improvement is seen, this will confirm that it is a mineral problem and not algae.  Repeat elsewhere as needed.  To help prevent a recurrence of the problem, add a double dose of a quality mineral remover.  There are pool stain scrubbers available to help remove difficult spots.  You might find more information in other areas of the archives.  I hope that I have been helpful.

Sincerely.  Alan Schuster, 3/10/2004

► Gray Stains?

I have a large in-ground pool/spa, 7 years old, kidney shaped, about 30,000 gallons.  It has had a Copper Ionization + ozone system on it for about 5 years.  Over the years, the pool service did not maintain the pH properly and the pool has developed gray stains.  A drain and acid wash is recommended by my pool service but I am reluctant to proceed due to the expense and the impact it has on the pool surface finish.  My pool technician, has suggested that he has been successful in treating stains like these with the addition of Muriatic acid to the water.  I am willing to give this process a try as it appears cost effective and should not damage the finish.  I would like to try the treatment on the spa first, and see if it is successful. If yes, than I would like to do it to the whole pool.  What are the pros and cons to this approach?  How much Muriatic acid needs to be added for success? My spa is 8 feet in diameter.  How many gallons of acid for the 30,000 gallon pool?  How long should I let this circulate?  Are there different strengths of Muriatic acid? Which one should I use?  What is the best way to restore the water chemistry after this operation?  Thanks.

Minoo B., 12/1/2003

I frequently recommend that a pool or spa be subjected to an acid bath as a means of stain removal.  Basically it dissolves the top surface and hopefully takes the stain with it.  Lowering the pH will subject the metal parts to corrosion, including the heater, if chlorine or bromine are present.  Therefore, treatment should be in terms of a short period of time - a day or less.  You have to add enough acid to lower the pH below lower pH readings on the testers.  A pH of about 5.5-6.0 should suffice.  Use the brush to scrub the surface.  Bypass the heater, if possible.  Once the stains are removed, add a dose of a quality metal treatment, in order to help avoid a recurrence.  Restore the pH and TA.  Because the addition of the metal treatment could interfere with the copper being introduced by the ionization unit, I would recommend using a polymer algaecide for a month or two, while the copper ion content is re-established.  I hope that this information proves helpful.

Sincerely.  Alan Schuster, 12/1/2003

I used your recommendation and the pool/spa surfaces are now to almost all-new condition. Thanks. There is one problem I am having that I have not been able to solve.  The pH continues to remain high (around 7.8 to 8), the TA is fine, and repeated attempts by my pool service and me to lower the pH by adding acid have not been successful.  My pool service thinks that the pool/spa surface areas are still leaching chemicals and are planning on adding some chemicals that will help.  Any suggestions based on your experience?  Sincerely,

Minoo B., 12/4/2003

It is possible that the walls are leaching into the water and causing the pH to rise.  To help prevent this, check the calcium hardness level.  If the level is below 200 PPM, raise it to that level.  If the calcium hardness is above 200 PPM, the answer to the problem may lie elsewhere.  I hope that I have been helpful.

Sincerely.  Alan Schuster, 12/4/2003 

► Well Water Stain Problem?

Alan, We have a 30,000 gal. in-ground pool that is filled from a private well on an ionization system with a sand filter. About (2) years ago, we started noticing dark stains in the pool. At first it was only on the fiberglass steps, but now we also have it forming on the vinyl especially in the deep end. By reading other articles by you, we feel problem is caused by iron from the well water (have noticed some staining in house toilets). If this is true, will adding a solution to the pool to remove these stains hurt the ionization system? Thanks. 

Tommy, 5/16/2003

Yes, the addition of a mineral treatment can affect the copper ions.  Have the water tested for iron and copper.  The copper at a few tenths of a PPM should be from the ionizer.  Any iron would be undesirable!  The iron should be treated with a mineral treatment: there is little choice in the matter.  Some of the ionizer manufacturers will advise you to add a dose of a chelated copper algaecide to maintain the effectiveness of the copper ion concentration.  Read the instruction manual for comments on this topic.  If it were my choice, I would forgo the addition of the copper algaecide, inasmuch as we are not certain about the cause of the staining.  Instead, I would add a quart of a 60% Polymer Algaecide and continue with the maintenance dose for another few weeks.  By that time, the copper concentration should have reached a new equilibrium.  There is a another solution, that can really make a difference with well water:  the METALTRAP pre-filter physically removes iron, from the pool, as the water is recirculated through the METALTRAP.  Using the METALTRAP, to treat all new water, helps keep new additions of iron and other metals out and minimizes the possibility of staining.  You could use The METALTRAP to recirculate the pool water.  It will remove the iron, as well as the copper.  Once done, you can test the copper level and replenish with a one-time addition of a copper algaecide.  Afterwards, use the METALTRAP when any new water is added, to prevent the introduction of iron and other heavy metals.  I hope that the advice proves helpful.

Sincerely.  Alan Schuster, 5/16/2003

► Brown Stains?

I have a 18x36  inground pool.  Rectangle with radius corners.  The pool is 6 years old.  We have brown-colored stain on the pool liner.  Is there any way to remove this?  What caused it?  We have never had this type of staining previously.  Thanks.

Becky S., 5/7/2004

It is difficult for me to know, with any certainty, what has caused the vinyl pool liner to become discolored and stained.  The problem could be stains from leaves and debris or a stain from algae.  If the pool was just opened, these possibilities are likely.  The colored stains could, also, be caused by the presence of heavy metals such as iron or copper.  Having the water tested for iron and copper could shed some light on these possibilities.  If you think the problem is leaves or algae, it, should be removed by shocking the pool water.  Raise the Free Chlorine level to 5-10 PPM.  This should show improvement within a day or so.  If the problem is minerals, you can try this as a means of confirmation.  Put 1/2 pound of pH reducer granules in a white sock.  Shut off the filter.  Drop the sock onto a stained area and leave in place for 15 minutes.  Use the vacuum pool to move it around. after 15 minutes.  If improvement is seen, the problem is definitely minerals.  To treat the entire pool, it will be necessary for the pH to be dropped to approximately 6.0.  This will dissolve the stains.  Use the brush to speed things up.  Afterwards, add 2-3 doses of a quality mineral treatment, in order to complex the minerals and help prevent a recurrence.  If you are on well water, using the METALTRAP Filter, to treat all new water, helps keep new additions of iron and other metals out and minimizes the possibility of staining.  You could, also, use The METALTRAP to recirculate the pool water and lower the heavy metal content.  I hope that I have been helpful.  Good luck.

Sincerely.  Alan Schuster, 5/7/2004

► Stained Gunite Pool?

Dear Alan, I tried your sock trick with pH decreaser and it worked on the stain. My problem is the pool store said that if I use to much muriatic acid to lower my pH to 5 it would destroy the surface of my gunite pool. They are in the business to sell chemicals.  Please advise as soon as possible.  Thanks.

Sincerely,  Alan Schuster, 11/11/2006

I tried the pH decreaser on the steps of my pool and also in the deep end I believe the stains to be iron since I use well water to fill the pool.  I  used a vitamin C tablet and it also removed the staining, but not as quickly.  How low can I lower my pH without adverse effects?  Also can I use muriatic acid since it is much less expensive then dry acid. I hope you have enough info. Sincerely.

Bill L., FL, 11/12/2006

You must have the pool and well water tested for iron.  You will need to add one dose of a quality iron treatment, for each one PPM or fraction - ASAP!  In the future add more after each addition of new water.  This will not remove the stains, but should help prevent more.  From what you are saying, it is apparent that acid will remove the stains.   That being the case, I suggest that you allow the chlorine level to drop to just a few tenths of a PPM.  Lower the pH to 6.0-6.5, by the addition of muriatic acid.  In this application, there is no benefit in applying dry acid.  It will only cost more and make zero difference in the corrosion.  Only the pH matters.  Once the pH is lowered, use the brush to scrub the stains.  Keep the filter operating and, if possible, by pass.  Periodically check the pH to see if more acid is required.  The acid will etch the upper surface of the walls and by doing so will help remove the pool stains.  The same etching would result from acid washing the pool.  The lower the pH - the faster the removal process.  Once the stains are removed, add another dose of iron treatment, prior to raising the pH.  If you can find a source of ascorbic acid, it might speed things up, if you add it just prior to adding the acid and while the chlorine level is very low.  This chemical will discharge all of the chlorine in the pool and will make a shock treatment necessary to restore a chlorine level, after the pH has been optimized.  However, before shocking allow at least 6 hours for the iron treatment to work.  Inasmuch you are on well water, using the METALTRAP Filter, to treat all new water, helps keep new additions of iron and other metals out and minimizes the possibility of staining.  You could, also, use The METALTRAP to recirculate the pool water and lower the heavy metal content, already present in the pool water.  I hope that this information will prove helpful.

Sincerely.  Alan Schuster, 11/12/2006

Dear Alan, thanks for the advice.  I did as you suggested and it worked out great.  The walls of the pool look great.  I will use an iron treatment, in the future, whenever I put water in the pool.  Thanks again.  Great site.  Good advice. Sincerely.

Bill L., FL, 11/15/2006

► Brown Walls And Bottom?

Alan,  Your pH-reducer-in-a-sock trick did WONDERS for our 7 yr old vinyl lined pool BOTTOM.  Within literally minutes, the brownish stains on the bottom disappeared. Problem:  The stains are still on the sides of the pool, however, and we cannot seem to get them off.  Our attempted solution.  We tried rubbing the sock on the sides, but were unable to stand there long enough for the trick to work.   We treated the whole pool, as you suggested, but the stains persist, only on the sides.  Any other suggestions?  Sincerely.

Sincerely.  Alan Schuster, 5/17/2004

Alan,  I LOVE your site, and have told all my pool owner friends about it!  As a follow up to my earlier question, we FINALLY got all the stains off of our pool.  In fact, it has never looked better.  We followed your advice about the pH reducer in a sock, and that got rid of all the bottom stains.  Then the local pool supply store told us to rub a lemon/orange/vitamin C tab on the stains to see if that got them off.  They started coming off instantly, so we went ahead and bought their stain remover product that was sheer concentrated ascorbic acid.  (Confirming what you said about acidic conditions being necessary).  We did not follow the instructions and broadcast the product in the water; rather we put it in a sock again and rubbed it along the sides. Thought the vitamin C thing might help someone else.  Thanks a million!

Alan: I have a gunite pool built in 1959. The previous owner's neglect has created brownish/black colored stains from leaves and there is also a very light greenish blue colored stain. I drained the pool thinking a muriatic acid wash would take care of this.  I was so wrong.  Using a 4:1, acid to water, it did not even scratch this stuff.  I need to get water back in the pool because of the massive amounts of rain we've had.  Please give me advice on chemicals, treatments, etc. I can't really afford to refinish and I was told that paint, because of the cratered surface, would peel quickly.

No Name, 5/13/2003

The brownish stains are probably tannins from the leaves.  Fill the pool up and a double dose of a quality mineral treatment, just in case the pool stains are more than tannins.  Add shock and boost the Free Chlorine level to 5-10 PPM.  Tannins will be destroyed by the chlorine.  Keep the Free Chlorine level elevated until the dark stains are removed.  Keep the filter operating and use the brush.  After these stains are removed, you will in a better position to access the appearance of the pool.  The greenish stains could be algae and/or copper.  If it is algae, the chlorine will take care of it.  I am no expert on painting the pool, but at the very least you will have to thoroughly clean the walls before painting them and this is a good start on that road.  One type of paint is especially easy to prepare for:  Ultra Poly One Coat.   Let me know how the first part turns out and we'll try to deal with the remaining problem.  Good luck and I hope that the information proves to be helpful.

Sincerely.  Alan Schuster, 5/13/2003

► Rusty Stains On Fiberglass Bottom?

Dear Alan, I recently had a fiberglass pool put in.(4 months ago) A short time later I saw my first couple of stains. One is a 2 inch streak 1/4 inch wide, my pool man who only ads the chemistry thought it might have been from a nail. I had a house built right next to the pool. The others seem more round and streaks like a meteor they are fairly small but I'd like to get rid of them without destroying the gel coat on the fiberglass.  Any suggestions are welcome.  The pool manufacturer thinks the pool guy might be adding the chemicals that settles on the bottom and causes these rust looking pool stains. Thank You.

Kris, 4/27/2007

None of the chemicals that the "pool guy" is adding should be capable of creating a pool stain problem.  There are two likely causes of a discolored or stained pool.  The source water added to the pool contains iron or other heavy metals.  You can confirm this by having the pool water tested:  most pool professionals offer complimentary water analysis.  The other equally likely possibility is a foreign object.  Start by adding a dose of a quality Mineral Treatment Product.  This will complex with iron and help prevent further staining.  To remove the stains, a good option would be to use a stain-remover accessory.  This inexpensive device is available at many pool stores and will allow you to siphon a solution onto the stains.  To make a suitable solution: to a 1/2 gallon of water, in a plastic container, add 1 quart of a quality Mineral Treatment Product and 1 quart of muriatic acid.  Make sure that you wear rubber gloves and eye protection!  Because your pool is still under warranty, I would discuss this treatment with the builder, so as not to risk voiding the warranty.  Use the stain-remover accessory to siphon the liquid onto the stains.  Afterwards, adjust the pH, as necessary.  Fiberglass pools have a negative electrical charge and can attract positively charged metallic ions, possibly causing the development of a stain.  Using the METALTRAP Filter, to treat all new water, helps keep new additions of iron and other metals out and minimizes the possibility of staining.  You could, also, use The METALTRAP to recirculate the pool water and lower the heavy metal content, already present in the pool water.   The periodic addition of a metal treatment should help maintain this condition and help keep pool stain free.   I hope that I have been of assistance.  Good luck

Sincerely.  Alan Schuster, 4/27/2007

That would most likely mean a leaking pool, if there were direct contact with the underlying soil.  Is there a significant water loss?  Otherwise, it is on the surface or in the gel coat and not through to the soil.  I would try some ascorbic acid, to see if it is a metals problem or some trichlor granules to see if it is organic matter.  Do them at different times.  Probably, an animal got in and you are looking at its decomposed remains.  Possibly, there is a defect in the finish and it is allowing water to penetrate to the fiberglass.  A little experimenting should narrow the possibilities and point to a solution.  I hope this proves helpful.

Sincerely.  Alan Schuster, 4/27/2006

► Stains From The Reverse Side Of Liner?

My pool has some grayish stains in the hopper.  I have tried everything; shocking, rubbing with a chlorine tablet and ascorbic acid and nothing has helped.  It seems to start in the spring and spread and darken as time passes.  The dealer says that it a fungus growing on the reverse side of the liner and I'll have to live with it.  Is there any suggestion that might help?  Thank you.

Mike T., 6/11/2009

Information on this topic is very sketchy.  The only person I had a conversion with, in depth, does not want to have his name made public.  He is not in the liner business and, therefore, does not want to handle the inquiries.  It is not a common problem.  But if you have the problem that is no consolation. 

Some types of bacteria and/or fungi, found in the soil, can actually appear to penetrate a vinyl liner and cause stains to appear on the liner. Usually they will start off as spots or cloud-like formations on the liner.  Chemicals used to elimination algae and other microorganisms have little or no effect, on these types of stains, since it doesn't get to the source of the microorganisms in the soil.

If a pool is thought to have a problem with microorganisms, mold or fungus staining reverse-side of the liner, the ground underneath the liner should be replaced with fresh sand, vermiculite or pool base.   Afterwards, treat with a solution of one-part liquid pool chlorine and three-parts tap water.   Apply with a garden sprayer several times.   Wait a few hours, before prior dropping the liner into place.  If it is not a new liner, please bear in mind that the liner could shrink and become useless, if allowed to dry out completely.  An alternative to the chlorine/water spray would be use a non-solvent based herbicide on fresh sand, vermiculite or pool base.

If the liner has been recently replaced, one method which has been discovered that may provide a solution.  The application of Ferrous Sulfate (FeSO4), to the perimeter around the outside of the pool can change the pH and the soil chemistry.  This chemical is a reducing agent and exhibits acidic properties.  This technique seems be effective in retarding and/or killing the troublesome bacteria, mold or fungus.   This stems from a method used to protect the vinyl liners used under some landfills.  This may not a guaranteed cure, but has been met with some success.  It can be tried without having to drain the pool and replace the liner.  For an typical inground pool, you might require twelve to fifteen pounds of this chemical.  Sprinkle it on the ground, around the outside pool perimeter,  near the pool patio or deck, on as much of the pool perimeter, as possible.  Afterwards, turn a lawn sprinkler on the area, for two or three days: long enough to get the ground around the pool thoroughly saturated with water. The intent is to get the ferrous sulfate to soak deep into the ground.   Hopefully, it will change the pH and soil chemistry enough and kill off or retard the growth of these troublesome microorganisms.  Results may not be seen for a few weeks, depending upon the nature of the soil's chemistry and drainage properties.  Direct application of chemicals can damage some plants or grasses, so abundant watering and drainage is important.  Ferrous sulfate is used with plants such as:  Rhododendrons, Azaleas, Blueberries, Mountain Laurel, Holly and Blue Hydrangea, that thrive best in acidic soil.  Do not allow this chemical to get into the pool, as it will cause water discoloration and staining of underwater surfaces.  An alternative to the surface distribution would be the digging of a series small holes around the pool perimeter and burying some of the ferrous sulfate, in each one.  Follow with a thorough watering down of the area, for the next few days.

I understand that the chemical is available at www.backyardcity.com  I hope that the information will prove helpful.

Sincerely.  Alan Schuster, 6/11/2009

► Ascorbic Acid Worked Immediately?

I have the light brown stains on a vinyl pool.  An ascorbic acid product worked the best.  Immediately the stains disappeared.  The problem is I can't find any locally.  Can you tell me of any other similar products that national pool places would carry?  Thanks.

Maria, 5/20/2004

Ascorbic acid be very effective in removing iron stains, especially if you can get the chemical to the strain.  It is functioning as an acidic reducing agent.  While many pool dealers carry the item, it is not in every store.  I have recently added it to the website store, because of people not being able to locate the product.  Click here to reach the right page. Good luck.

Sincerely.  Alan Schuster, 5/20/2004

► The Tough Last 10%?

Sincerely.  Alan Schuster, 6/20/2003

 

► Stains All Gone!!!

We took your advice and used a metal treatment product. Brown stains on steps are gone!  I am so disgusted when I think of what we have done this summer and last!  Two different companies tested the well water and pool water for metal and said there was none!  How often, as a general rule, should be use the metal treatment product?  The bottle did have a maintenance dosage amount recommended.  Thanks so much!

Debbie H., Montgomery, Alabama, 10/26/2003

Pool stores usually only test for iron and copper.  The problem could have been another metal or there was something in the water that interfered with the test.  The main thing is that your problem sounded like it was caused by a metal.  Follow the maintenance dosage, as specified on the label, and add monthly and whenever new make up water is added.  Inasmuch you are on well water, using the METALTRAP Filter, to treat all new water, helps keep new additions of iron and other metals out and minimizes the possibility of staining.  You could, also, use The METALTRAP to recirculate the pool water and lower the heavy metal content, already present in the pool water.  There is no set rule for these things, as much depends on the metals content and the overall pool chemistry.  More often is always the safer choice.  Glad it all worked out.

Sincerely.  Alan Schuster, 10/27/2003

► Algae Stains Or Mineral Stains?

Hello Alan.  You have a great web site. It has been so helpful. I do have a pool stain problem with my in ground 16 X 38 pool. I have some stains that appeared in the bottom of my pool. It is a vinyl liner. All of the stains are at the bottom where the side walls meet the bottom and at the corners of the slopes down to the deep end. It is tan and beige in color. I tried scrubbing the areas and no success. I was told to try putting a 3" tablet in a sock and scrub the area and see if it lightens up. That did not work either. I was told that it could be black algae and I also was told that it could be a metal stain. The testing of the water showed no metals in the water. What would be my next step?  Any help would be appreciated.  Thank You.

Ralph, 6/13/2003

I would advise you not to try that thing with the tablet in the sock.  It might work, but it might bleach the liner.  You can remove a stain, but you can't undo the bleaching out of the liner color.  The areas that you are describing are some of the favorite hangouts of algae.  It is also possible that mineral particles accumulated in these areas and led to the discoloration.  From the color it is not clear cut, as to the possibilities.  The fact that the water does not show metals is not conclusive.  The metals may have precipitated out of the water or may not have been tested for.  I suggest that you start by trying my sock trick.  Put 1/2 pound of pH reducer in a white sock and drop onto a stained area.  Position with a vacuum pole, if necessary.  Leave in place for 1/2 hour.  If the pool stains are removed, it is proof that the problem is mineral.  If this did not work, try it with ascorbic acid, instead of the pH reducer.  Refer to the archives on pool staining for more on stain removal techniques.  If the discolorations and stains are not removed, it is possible to probable that it is a resistant type of algae.  If this is the case, I suggest that you treat it on the basis of black algae.  You'll find more information in the archives on that topic.  I hope that this information will point you in the right direction.  Good luck and let me know how it turns out.

Sincerely.  Alan Schuster, 6/13/2003

► Stains Caused By Leaves?

Do you know of a stain remover that will work on leaf stains?  We had a problem when closing the pool, and the water was not clear, and leaves set all winter.  The pool now has a green tint, and looks like algae, but tests good

You don't need a stain remover.  Most likely the stains are tannins from the leaves and would have resulted in brownish colored stains.  The green color of the pool water is. most likely, due to algae.  Shock the pool and keep the Free Chlorine reading at approximately 5 PPM, until the water clears up.  The elevated chlorine level will decompose the tannins and the algae at the same time.  Use a brush on the stained pool surfaces to speed things along.  Keep the filter operating continuously.  Retest the Free Chlorine periodically and add more shock as might be required.  After the water clears and the stains are gone, resume normal filtration and chlorination.  A solar-powered, pool surface skimmer can remove the leaves, before they have a chance to sink to the pool floor.  I hope that I have been helpful.

Sincerely.  Alan Schuster, 4/20/2003

► Cause Of Exposed Aggregate Stains?

I have a 1-year old pool running on a salt chlorinator.  The water balance has been maintained pretty much dead center.  However, on two occasions the salt system blew a fuse and stopped generating chlorine for a week.  In the shaded area of the pool I developed algae after the second blown fuse.  I’ve been told that the discolored areas now on the exposed aggregate surface are algae that have impregnated the surface.  I’ve tried recommended doses of stain removers for yellow, non-metallic type stains with some success.  The stains have definitely been lightened, but they’re still there.  My questions: Is my information correct; have algae impregnated themselves into the aggregate? Can I double or triple the dosage of products recommended for removing that sort of stain?  Is there a product on the market that will work well on this sort of stain?  Lastly, I know algae can grow quickly, but, I’m skeptical that this stain was caused within a 1 week period, simply because of the salt system shut down. I’ve had pools in the past with tons more algae and never any staining.  Could this be because the surface was so new when the outbreak occurred?  It happened within 3 months of being filled with water.  Thanks for your help.

Mark M., 2/3/2005

I can point you in the right direction, but the exact cause is for you to discover.  Algae can grow very quickly, especially in warmer water that is lacking chlorine.  Algae can stain and get imbedded in the rough surface.  Given that the salt chlorinator was inoperable for a week, this seems the most likely cause of the problem.  Metals can stain, especially in a pool that is relatively new.  I doubt that there was anything inherently wrong with the finish.  So which is it?  Adding all the metal treatments will do nothing, if the problem is algae-related.  A high dose - 10 PPM - of free chlorine would be much better in this case.  Try and redirect the flow to send more water towards the effected areas.  If the stain is metals-related, shocking the pool will accomplish nothing.  You might need to lower the pH and add some ascorbic acid, after the chlorine level has been dropped closer to zero.  Read through the archives on pool stains and give the sock trick a try or place a few vitamin C tablets on a stain.  If this works, the problem is definitely metals.  If it fails to work, it is most likely algae.  Good luck and I hope that the information proves helpful.  Please let me know how it turns out.

Sincerely.  Alan Schuster, 2/3/2005

► A Wintertime Mistake?

Greetings Alan, I came across your website and I am unclear if some of the questions pertain to me. We covered our pool last winter with the cover and tied most of it off. During some windy days my husband put some weights round the pool to hold the liner down, unfortunately one fell in and left quite a large size rust mark. We live in the Toronto Canada area and are looking for ways to scrub away the rust stain. Some removed with a pool brush however there is a significant amount left.  Could you please assist!  Thank You.  First time pool owners.

Dale and Jacquie H., Toronto, Canada, 6/10/2003

I'll assume that the pool is vinyl lined.  Try this!  Put 1/2 pound of pH reducer powder in white sock and drop onto a stain - use the vacuum pole to position the sock.  Leave in place for 15 minutes.  If improvement is seen, repeat elsewhere, as needed.  If it doesn't work, you might try using ascorbic acid instead of the pH reducer.  You can also use a stain-remover accessory to remove the stain, by siphoning an acidic cocktail onto the stains.  This device is available at many pool stores.  In the future, use water bags to hold the winter cover in place.  Good luck and I hope that I have been helpful.

Sincerely.  Alan Schuster, 6/10/2003

► Stained By Neglect?

Hello, I appreciate your advice.  I am a new home owner with a new pool, which is said to have been re-plastered last year w/ blue plaster.  I expected the pool to be in good shape when we moved in. However, it appears the previous owner had stopped maintaining the pool for at least two months.  By the way, this is in El Paso.  We get high winds this time of year with lots of dust, the pool has no cover.  I immediately vacuumed the pool and tested the water.  It was low on chlorine. I expected the floor of the pool to get clean completely.  However, I was surprised to find that not all of the dirt came up.  Throughout the floor of the pool there is a faint grayish layer of what appears to be dirt.  However, there appears to be tracks running back and forth along the whole bottom of the pool, that I would assume were made by the wheels of a vacuum.  These tracks run back and forth in predominantly one direction, and the pool surface looks clean where the tracks are. I don't know how to describe it further, other than the bottom just looks dirty with all these "clean" tracks running through it. Can you help with any advice?  Your recommendations are greatly appreciated.

Frank H., El Paso Texas, 4/25/2003

There are several possibilities.  The neglect could have resulted in algae and debris accumulating and causing a discolored, stained pool.  If this is the case, a shock treatment should remove the discoloration.  Boost the Free Chlorine level to 5-10 PPM and keep it there for a few days.  The problem could be minerals.  A water analysis should shed some light on this possibility.  Have the water tested for iron and copper.  You might try this.  Put 1/2 pound of pH reducer powder in a white sock and drop onto a stained area.  Shut off the filter and allow to remain in place for 15 minutes.  If improvement is seen, the problem is minerals.  If no improvement is seen, algae and debris staining are more likely.  Your local pool store should have a gadget that can attach a 3" inch tablet to the end of a vacuum pole.  Use this to rub a chlorine tablet on a stained area.  If improvement is seen, the shocking of the pool should do the trick.  Browse through the archives for more on this topic.  Good luck and I hope that I have been helpful.

Sincerely.  Alan Schuster, 4/25/2003  

You've given me some good ideas on how to proceed.  Sincere thanks for your response.

Frank H., 4/28/2003

► Mystery Stains?

The pool store we used closed this past year.  Right after that, we installed a chlorine generator on our 18 x 48 inground vinyl lining pool.  We always had clean sparkling water with chlorine, and for the first couple of months, the water was fine with the generator.  Now the sides of the pool have become stained.  This LOOKS like an algae but it is a stain - even the stainless steel ladders have stains around the water level.  This baffles me!  The generator registers 2800 to 3200 so I'm sure we're putting enough salt in the water.  Is this a normal occurrence with these generators?  We've always had the prettiest pool in our neighborhood and now it looks like it's dirty.  I know the water is clean though.  I worry that, should we put in a new liner, will it become discolored too?  If you can help me, I surely would appreciate it!

Colleen,  Central Georgia, USA, 5/12/2005

The stains are probably due to iron, copper and other trace minerals and are rarely removed by simply adding a metal treatment. The stains are probably completely unrelated to the salt chlorine generator.  Try this.  Place 1/2 pound of pH minus in a white sock and drop onto a stain.  Leave in place for 15 minutes.  Move around with a pole.  If this works, you should be able to get rid of the stains by lowering the pH of the pool to about 6.0.  If you have a heater, by pass it or allow the chlorine readings to fall to zero.  In it does not work, place a few vitamin C (ascorbic acid) tablets on a stain, shut off the filter and leave in place for 15 minutes.  If this worked, it is likely that treating with ascorbic acid will work.  Put 1/2 pound in a white sock and drop onto a stain.  Slowly move around with a vacuum pole.  Repeat elsewhere, as necessary.  Some pool dealers carry these products.  Have the pool and source water tested for iron and copper.  ADD A DOSE OF A QUALITY METAL TREATMENT FOR EVERY 0.5 PPM OF IRON OR COPPER.  At the very least add two doses.  If the stained area is too broad to be treated with the "sock", you may have to lower the pH of the pool to 6.0, discharge all of the chlorine and add a few pounds of the oxalic or ascorbic acids.  If there are questions regarding this get back to me with the test results and the results of the "sock" test.  Thereafter add a dose of metal treatment monthly or prior to adding new water, in order to avoid minimize the possibility of a recurrence.  Good luck and I hope that I have been helpful.

Sincerely.  Alan Schuster, 5/12/2005

Alan, I just found your letter - I'd saved it.  Just thought I'd let you know, I just took a sample of the water to a pool store and bought what they recommended and did what they said!  You were so kind to try and help me out!  I just need a "pool man" to come every week.  Actually, life with the chlorine generator is simple.  I just know now that I still have to test my water.  Have a happy and safe Memorial Day.

Colleen, 5/29/2005

► Rust?  

We recently did some work in our back yard using steel wool.   Particles of the steel wool ended up in our inground pool.  Small rust stains from the steel wool are appearing.  Is there something I can use on these small stains to remove the rust without emptying the entire pool?  Thanks.

Mike C. Scottsdale, AZ, 10/2/2003

First start by adding a dose of a quality Mineral Treatment Product.  This will chelate (complex) with iron and help prevent further staining.  To remove the stains try this: put a pound of pH decreaser in a white sock and drop onto a stained area.  Leave in place for a few minutes and slowly move to other areas with the vacuum pole.  It should dissolve the stains.  A better option would be to use a stain-remover accessory.  This gadget (available at many pool stores) will allow you to siphon a solution onto the stains.  To make a suitable solution: to a 1/2 gallon of water, in a plastic container, add 1 quart of a quality Mineral Treatment Product and 1 quart of muriatic acid.  Make sure that you wear rubber gloves and eye protection!  Use the device to siphon the liquid onto the stains.  Afterwards, adjust the pH, as necessary.  Another type of accessory allows you to scrub the stains away and might be a simple and effective way to deal with the problem.  I hope that this information proves helpful.

Sincerely.  Alan Schuster, 10/2/2003

► Product Of Neglect?

Great website, I have found it very useful.  I have a problem with some staining on the plaster of my in ground gunite pool. I read through the replies to other's problems and didn't see this addressed.  The pool is about 7 years old and was not taken care of by the previous owners.  We inherited it 2 years ago and it was green and dirty with the staining I describe below.  I have heard from neighbors that it was partially filled and left unattended for some time.  I have had a pool service for the last 2 years.  I took the water in to a local store today and it had:  Free Chlorine=5.0, Total Chlorine=5.0, pH=8.0, TA=260, CYA=90, Calcium Hardness=1075 (very high!), TDS=2500+ (very high!, off the scale they had).  They pointed out that the TDS was extremely high and that the pool should be drained and refilled.  Also the CH was very high.  I am in San Diego, CA, where we have hard water, but the store said that the CH from the tap is about 200, so tap water should be fine.  Here is the problem.  I have a medium to dark blue plaster finish and there is some staining or discoloration on the uppermost step (foot step) and the bottom at the deepest part of the pool (about 6 feet deep) around the drain, maybe a 5 foot diameter area.  The discoloration looks like the dark blue finish has lighten up to almost light yellow to white, it is very uneven and erratic in color, almost like something has eaten into it, although the surface is not unusually rough.  The discoloration at the top step (there's none or very little on the lower steps) appears to be a result of the floating chlorine tablet holder floating over or sitting above the step, almost like the chlorine leaching out of the floater and bleaching out the color in the plaster.  The staining in the deeper part of the pool looks similar.  My pool service guy believes that the color in the plaster has been bleached out.  His explanation for the staining on the bottom of the pool is that someone previously placed chlorine tablets in the skimmer basket, which created a high concentration of chlorine when the pump was off, and this concentrated liquid traveled down the pipe (since the bottom suction pipe comes up just below the skimmer basket) to the bottom drain and had a similar bleaching effect as the step had.  There are some spot stains around the pool in various spots, maybe 2 inch diameter, and he felt that small pieces of chlorine tablets may have fallen out of the floating chlorine tablet dispenser and stained the bottom. He felt that the pool would have to be replastered to fix the stains.  Since my pool chemistry is pretty out of whack, I am feeling less confident in the answers I am getting from him.   What are your thoughts?  Would acid washing work?  Can the plaster lose its pigment/color from chlorine?  Any guidance would be very helpful.  Thanks.

Ron L. San Diego, CA, 2/11/2004

Obviously, the pool was badly neglected.  That may be the only certain fact!  The skimmers connect to a valve near the filter and not directly to the main drain.  There's no likelihood that backflow caused these problems.  It is not likely that trichlor tablets were, necessarily, used for long periods of time - otherwise the cyanuric acid level would have been much higher.  If the water was partially drained to lower the CYA reading, why are the calcium and TDS so high?  To me it sounds like your pool has experienced severe etching, possibly to deal with scale deposits.  The fading colors may have been caused by chemical action.  The pool is 7 years old and a refinishing is, at best, a near term expectation.  You could drain the water to lower the calcium hardness, which is really too high for proper pool water management.  You could try to acid wash the pool, but from your descriptions, it does not sound like it will do an effective restoration job.  Why spend money on acid washing, chemicals and replacement water, only to decide later that the only and best hope is a resurfacing of the pool?  I would opt for the pool resurfacing, if it is a budgetary option.   After the pool is back to prime condition, I would suggest that you use an alternative means of sanitizing, in order to better preserve your investment and have fewer water chemistry problems to deal with.  Ozone, salt chlorine generators or UV Sanitizing are some of the methods that will replace the chlorine floater or the tablets in the skimmer (always a bad idea).  I hope that I have put you on the right path.

Sincerely.  Alan Schuster, 2/12/2004

► The Whole Stain?

I would like to refer back to this question from Ralph, 6/13/2003.  My uncle had this stain and tried your solution, the pH reducer, and it removed the stain.  But I cannot find a solution to removing it from the whole pool.  Please help!

Lisa, 7/10/2003

If the sock trick worked, it is likely that lowering the pH of the entire pool will remove all of the staining from the pool walls, bottom and steps.  Add muriatic acid to drop the pH to approximately 6.5.  You'll probably have to guess with the test kit.  Make sure that it will well below 6.8.  If possible bypass the filter and heater and keep the water moving.  Use the brush on the walls.  Retest the pH periodically to make sure that it is remaining low.  If possible, allow the chlorine level to remain low.  Once the stains are removed, add several doses of a quality mineral treatment.  This will help complex the offending mineral and help avoid a recurrence of the problem.  Allow 4-6 hours for the mineral treatment to be distributed and to react with the redissolved minerals.  Slowly raise the pH back to normal ranges.  In the future add a dose of mineral treatment before each addition of new water.  I hope that the information proves helpful.  Good luck and enjoy the summer.

Sincerely.  Alan Schuster, 7/10/2003

► Staining Down Under?

Hi, I'm from NSW Australia and have come across your site. Hope you can help me as no one over here can. I have a fiberglass, salt pool that I am very fanatical about keeping clean. I keep getting a brown stain, that with the assistance of my local pool shop I get rid of only for it to return a couple of weeks later. My cartridge has been stained red from this stain. It starts out on the bottom of the pool only up the middle about 1 & 1/2 meters wide and then goes onto the sides. I keep my pH at about 7.2, alkalinity is usually about 60 as I hate to keep adding acid to keep the pH low as per the pool shops instructions to keep the stain at bay and chlorine levels are always correct. I test my water daily. Over the past 2 months the salt cell has been clogging up on a weekly basis, where before it would take a month. The local pool shop has tested the water for minerals only to tell me each time that it tests clear. I have been getting rid of the stain with acid but it always returns after about 2 weeks. I use a product that is supposed to remove the stain from the water and we clean the filter cartridge weekly. Can you suggest something that may be in the water that is causing this? Thanks.

Oz, Australia, 4/16/2004 

It definitely sounds like a mineral stain. The fact that the local dealer is not testing positive does not preclude this possibility. Minerals can be present and because certain types of chemicals have been added by either the water utility or the pool owner, it is possible that the testing procedure is encountering interference. Iron is most likely the mineral causing the problem. I suggest that you treat the problem with a concentrated Quality Mineral Treatment. In addition, to treating any iron and heavy metals, it will help keep scale deposits from forming on the salt/chlorine cell. The low pH approach is not a long-term solution. You could look into something that will make cleaning the filter cartridge easier:  The Blaster. For complete product information go to:  www.neoterics.com   I hope that this will prove helpful. Good luck!

Sincerely. Alan Schuster, 4/17/2004

► Blue Stains and Black Spots?

We enjoyed your site and have made use of your suggestions on blond hair turning green. Now we have another problem. The top steps at each end of the pool and the sides of those steps have developed turquoise blue stains all over them. Why? Also, we are getting little black dots (or spots) on the bottom and sides of the pool. Here's a little history on our pool. It is a one year old, gunite and plaster pool, 13 X30, full sun and we started using an aluminum solar blanket this past March. We did not have this problem or green hair last season. It is not a heated pool nor is it connected to a spa. The only thing I know that I did wrong this year was to allow the chlorine level in the pool to run out for about one to two weeks starting Memorial Day. We also had the blanket on during this time as well and forgot to check the chemicals. (We do our own testing and maintenance). During this period the pool temperature hovered between 86 and 90 degrees. The blue stains only appeared on the step surfaces closest to the water surface. I also want to mention that our small filter, that we clean and check twice a week, has an Ionizer in it. Also, after discovering my chlorine snafu, I tossed 5 chlorine tablets into our floating basket, waited a week or two and then had the water professionally tested, after my wife's hair turned green. The testing showed the pool only needed a little muriatic acid and all the other levels were fine including pH. My wife's hair doesn't seem to be turning green anymore and if we scrub the blue stains with a pumice stone, some stains disappear with A LOT of elbow grease. No amount of  scrubbing takes the black spots off. Any suggestions? I hope that we haven’t been overly windy. Thanks for any help that you can give us.

Miles P., Henderson, NV, 9/2/2004

The green hair and blue-colored stains could be from copper. The question remains, how much copper is detectable and, if the level is more than a few tenths of a PPM, it is very likely the Ionizer is providing too much copper. Check the settings or controls and review the operating manual. If there is no copper present, the green discoloration of the hair could be due to the chlorine reacting with hair products. The blue stains could be algae. The black spots could be algae, other minerals or a copper stain, in the presence of high calcium hardness levels. Try this!  Place a 3" tablet of top of the pool stain and allow it to remain there for a few hours (the tablets can affect some masonry finishes, so either test it on an inconspicuous spot or verify suitability with the finish contractor). If the problem is algae, you should see improvement. If not, try placing a sock with a 1/2 pound of pH Minus on top of a stain. Shut the filter off and allow to remain in place for 15-30 minutes. If improvement is seen,  the problem is minerals. Adding a mineral treatment product could interfere with the Ionizer.  Check the manufacturer's recommendations on treating heavy metals, in a pool with an Ionizer.  I hope that I have been helpful.

Sincerely.  Alan Schuster, 9/3/2004

► Ascorbic Acid Works.  But?

Alan, I have a 30,000 gal gunite/plaster pool and read that you recommend shocking rather than ascorbic acid for tannin stains.  I get these stains often (once or twice a year due to a large oak tree) and always remove them successfully with ascorbic acid.  I would love to use the shock treatment for the ascorbic acid costs about $100 per treatment, but the shock treatment doesn't work for me.  I shock once a week during the summer and once a month during the winter.  Am I misdiagnosing and really have something other than tannin stains for which ascorbic acid also works?  Thanks in advance.

Joe P., 5/28/2006

Chlorine destroys tannins.  Plain and simple.  If it doesn't work in your case, it is probably not tannins or tannins and a heavy metal stain.  I realize the ascorbic acid is expensive, but it works best against heavy metal stains.  Follow with a dose of a metal treatment.  Add more metal treatment prior to the addition of new water.  Once you remove the stains, you could do something that will help make sure there are removed permanently. Using the METALTRAP Filter, to treat all new water, helps keep new additions of iron and other metals out and minimizes the possibility of staining and discoloration.  You could, also, use The METALTRAP to recirculate the pool water and lower the heavy metal content, already present in the pool water.  It is definitely easier than using ascorbic acid and, probably, less expensive in the long run.  I hope that I have clarified the problem.

Sincerely.  Alan Schuster, 5/28/2006

Sincerely.  Alan Schuster, 5/3/2004

The algaecide treatment and shock treatment, combined with chlorine tabs on each spot, successfully removed the stains.  I also pressure washed to clear the top of the screen enclosure of debris.  The problem is, after the pool looked great, when I went to bed.  However, this morning new spots appeared, about 50 of them, in the same areas, but not the same spots.  I have no idea what's going on, but I'm frustrated as hell.  Any thoughts or suggestions?  Thanks.

Mike, 5/5/2004

The stains are not copper or another metal or else the chlorine would not have removed them.  The plaster spot problem that has been widely reported does not respond to chlorine.  That only leaves algae or some organic type of stain.  Have you ever added a metal treatment?  Is your pool overhung by a tree, such as a live oak or black olive?  If chlorine was the solution, it seems that the oxidation function is inadequate, on a 24-hour basis.  Perhaps, you should simply maintain the pool on a very low level of chlorine, so that there is always some present, for those times with active oxygen is not being produced.  Using bromine would be even better, as it seems more effective against certain problem types of algae.  It would be safe to assume that the copper is not able to control the problem, possibly due to the addition of metal treatments.  Add a polymer algaecide and continue for a few months.  I suggest that you shock the pool, raising the free chlorine level to 5-10 PPM.  Use the brush and improvement should be forthcoming, in a day or so.  Good luck.

Alan, 5/7/2004

Yes!  There is a live oak above that area of the pool.  Has that been known to cause this or similar problems?  No, I have not used a metal treatment because the manufacturer of the copper system said not to.  I agree it must be something organic, but damned if I know what it is, particularly since the stains show up so quickly.

Mike, 5/9/2004

Hi Alan, I followed your advice and had the tree cut back away from the screen enclosure.  Shocked the pool, and the stains disappeared permanently!  I plan on keeping a little chlorine present, just as a backup.  Thanks so much for your patience and help.  You have a great website!

Mike, 6/4/2004

Editors Note.  In the final analysis it was simply a matter of there being no chlorine or oxidizer present during the overnight period.  The problem was not attributable to copper staining. It was simply a matter of fine particles of live oak tree debris falling into the pool and leaching tannins, after the pool was shut off at night.  The solution:  maintain a low level of chlorine, with the copper-oxidation unit.  5/10/2004

► Seeing Yellow?

I have a marcite pool that has been in for 8 months and it has gotten yellow-colored blotches on the bottom and the steps. The pH, chlorine, alkalinity levels are ok. I brush the pool each week. I was told the calcium would cause this. I have shocked it and I have put in a gallon of chlorine every two weeks.

Kendell W., Sarasota, FL, 3/12/2004

The yellow color of the spots could be attributed to several causes:  iron stains, algae growth and discoloration caused by fertilizer granules.  An Iron Test can measure the presence in the water.  Try the following to help narrow the choices and point to a solution.  Put 1/2 pound of pH decreaser in a white sock, shut off the filter and drop onto a stained area.  Check after 1/2 hour. If there is a noticeable improvement, the likely cause was iron, in the water, or possibly fertilizer granules. Repeat this elsewhere, as needed to remove all of the stains.  If the area is extensive, it may be necessary to drop the pH of the water to 6.5 or less.  After the stains are removed, add a Quality Mineral Treatment to help prevent a recurrence.  Thereafter, add more of the product, prior to the addition of any makeup water.  Restore the pH to 7.2-7.6.  If the "sock treatment" did not work, the likelihood is that the problem is algae or even stains from leaves.  Place a 3" chlorine tablet on a stain (NOT FOR VINYL POOLS), shut off the filter and allow to remain in place for a few hours (the tablets can affect some masonry finishes, so either test it on an inconspicuous spot or verify suitability with the finish contractor).  If improvement is seen algae or discoloration caused the stain.  You can use Polymer Algaecides, shock treatment and well-placed trichlor tablets (NOT WITH VINYL POOLS).  Broader areas can be treated with a granular trichlor (NOT WITH VINYL POOLS).  Calcium is usually associated with scaling or cloudiness. Yellow discoloration is not a characteristic of calcium.  The discoloration is probably not related to any defect in the marcite finish.  I hope that I have been helpful.

Sincerely.  Alan Schuster, 3/12/2004  

► Staining Caused By A Black Olive Tree?

My neighbor has a black olive tree near our property line and a couple of times a years, it "drops" a lot of debris.  Leaves and seeds get into the water and not all of them end up in the skimmers.  The ones that fall to the bottom cause a brownish stain.  Shocking will get rid of the stains, after I have removed all the junk.  Is there anything else I can do.  I hate that tree.  Thanks.

Larry A., Boca Raton, FL, 7/17/2003

I have had the same problem myself.  You are correct to shock after removing the "junk".  The stains are the result of Tannic Acid leaching from the leaves.  The stains occur after the leaves have remained in contact for a period of time.  You might consider an automatic pool cleaner.  It will help remove the leaves before staining can develop.  It will help, but is not an absolute solution.  There is no magic chemical.  Another way to deal with troublesome leaves is to remove them, before they get a chance to sink to the bottom.  A solar-powered, pool surface skimmer will be on guard, scooping up all sorts of floating debris.  It will reduce the staining, reduce the need to vacuum and even help distribute chemicals.  Sorry that I couldn't be more helpful. 

Sincerely.    Alan Schuster, 7/17/2003

► Major League Mineral Problems?

Sincerely.  Alan Schuster, 5/16/2003

Editors Note:  it took a few days longer and a few more e-mails, but the pool finally cleared up.  The problem was the manganese.  Such a large volume of mineral treatment was required, because other minerals were present and were competing for the chelating agent.  5/20/2003

Editors Note:  Six years have gone by and treatment options have changed as well.  The following is how that pool should be treated, today.  Inasmuch you are on well water, using the METALTRAP Filter, to treat all new water, helps keep new additions of iron and other metals out and minimizes the possibility of staining.  You could, also, use The Metal Trap to recirculate the pool water and lower the heavy metal content, already present in the pool water.
7/19/2003

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