bromine santizers, chlorine-free water chemistry & sanitizing, for spas and swimming pools

Bromine is much more popular in spas and hot tubs, than in swimming pools. For use in spas and hot tubs, it is available in two forms: slow-dissolving tablets or a quick-dissolving 2-part system. Bromine, in functioning as a sanitizer, produces less odor than chlorine and tends to be less irritating. The use of bromine is popular as a backup sanitizer or oxidizer for Ozonation, Mineral Sanitizers or Ionization. Clicking on the underlined and highlighted "keywords" or "catch phrases," in the archived answers will give you access to additional information on that topic or product. Please refer to the Glossary, if there are terms or phrases that require explanation. For an alphabetized listing of the entire contents of the website, use the Table of Contents link, on top of every page.

I can understand how the bromine tablets work. That's fairly straightforward. The 2-part bromine seems a bit confusing. I'm using it, but I don't really understand how it produces bromine. Can you help?

There are 2 products that comprise the bromine 2-part system: a liquid product containing a concentrated solution of sodium bromide and a granular product containing the oxidizing agent potassium peroxymonosulfate (also called potassium monopersulfate or monopersulfate compound). The liquid product is typically added only once a month. Adding more will not produce more bromine. The granular product is usually added on a daily basis or, as needed, and it is this product that results in bromine being produced. The potassium peroxymonosulfate reacts with the sodium bromide, already in the water, and forms bromine. Add more potassium peroxymonosulfate and more bromine is produced. After, the bromine has been consumed in the sanitizing process, it reverts back to sodium bromide, allowing for the cycle to be repeated. The sodium bromide product is added monthly to assure that there is always an excess amount of bromide, available to be converted into bromine. The water can be tested for Bromine and adjusted accordingly. The advantage of this method is that it is quick dissolving and allows for flexible control of the bromine level. The 2-part system produces no organic byproducts and contributes only harmless, innocuous salts to the water, after the sanitizing is completed. Hence, never a build-up problem. These products are pH buffered, so as not to have a major impact on the pH. The only downside is that you have to add it more or less on a daily basis. I hope that I succeeded in explaining the product. Enjoy the spa.

We purchased a spa a month or so ago. The chemicals that came with the spa were not bromine or chlorine, so two weeks ago I drained the spa and started using bromine tablets and a pH balancer that they suggested I add. .However, every time I test the water the levels for Bromine are at 0 - very low, even though there are tablets in a floater. Also, the pH is around 6.8 and the alkalinity is very high - 240. What chemicals should I add to get the water in balance? I have read of lot of your website, and it appears as though I need to get a bromine shock treatment, but I want to confirm before I do it. Thank you for your help.

Bromine tablets are slow dissolving and, as such, do not play catch up very well. You need to add shock treatment - either dichlor or a non-chlorine shock - to boost the bromine level into the 3-5 PPM range. Thereafter, keep the bromine floater full and add more shock after periods of heavy usage, at first signs of loss of water quality or whenever the bromine level falls below optimum. Bromine tablets are acidic and will lower the pH, as they dissolve. Add pH increaser, as necessary, to raise the pH into the 7.2-7.8 range. This is important for bather comfort and to help protect the heater from corrosion. While your TA is high, it may not be necessary to lower it, so long as the water is clear and there are no signs of scaling. The addition of an ozonator is something that you might consider, as it will make maintenance easier and produce higher quality water. I hope that I have been helpful. Enjoy the spa and have a happy Halloween.

Hi! I read your article, "Bromine for Spas", but I could not find any information as to how to actually add the tablet to the water using a floater. I was curious as to if you could give me a description of how to do this. For example do I leave all tablets in the bottle and put it in the tub? Or do I put one tablet in the floater? Thanks!

A simple enough question that seems not to have been asked before! A floating feeder for a spa is relatively small (compared to pool feeders) and probably is able to contain 6-12 tablets, depending upon the actual design. Start by filling the feeder and trying to keep the feeder relatively full, by adding more tablets 1-2 times weekly. Do not allow the tablets to completely dissolve before adding more! Keeping the feeder reasonably full will help allow for a more consistent dissolution of the product. Use the adjustments for opening and closing the water vents, to help maintain the bromine level at 3-5 PPM. Bromine tablets are slow dissolving and do not play catch up very well. You should add some shock, after periods of heavy bather usage or whenever the bromine level has bottomed out. You might consider adding an ozonator, as it will reduce the amount of bromine necessary and allow you to maintain a low level of 1-3 PPM. I hope that I have been helpful and enjoy the spa.

I have a question for you and I hope you can help me. I was using the part 2 Bromine system (Part A and B) I had no problem but I changed to the Bromine tablets and automatic dispenser (floating device) because I found that the 2 part requires more care and If you are not home for a few days than the chloride (bromine) level will be too low. Now since I have the tablets I can not get the level to be appropriate, I am using the sticks and there is no Bromine at all! I open the dispenser to the maximum and still no Chlorine on my results? any ideas? Thanks.

The bromine tablets are very slow dissolving. They do not play "catch up" very well. Depending upon how your spa is being used, you may have to supplement the bromine tablets with some addition of the oxidizer portion of the 2-part system. This will give an instant boost to the bromine level and make it easier for the tablets to keep pace with the demand. Adding some of the product after each use of the spa is another way to help maintain a proper level. Have you ever considered an ozonator? Combined with the bromine floater, it should provide very good results with less bother. I hope that I have been helpful.

I have been using bromine tablets in my spa. The results, so far, have been good, but I would like to use less bromine and fewer chemicals. Any suggestions would be appreciated. Regards and thanks.

The simplest thing to do would be to add a Mineral Sanitizer. Because you are using bromine, you can't use just any mineral sanitizer, as some cannot be used in spas that contain bromine. THE FROG Mineral Sanitizer can be used in spas, that use bromine or chlorine and it will not interfere with the expected 6-month life of the cartridge. For more information of the full line of FROG Mineral Sanitizers go to: www.kingtechnology.com The presence of the mineral sanitizer will allow you to maintain a lower bromine level and because less bromine will be used, the overall water chemistry will be easier to control. I hope that this information proves helpful.

I just purchased my first home it has a pool and a spa. I let the pool guy take care of his end but I manage the spa levels. When I moved in the spa was full, with a Bromine Floater. I tested the water several times with a kit that was here when I moved in, 5 drops of yellow stuff, 5 drops of red stuff you know the kit. I always got very high bromine levels. Not sure if I was testing correctly I took a water sample to my local pool/spa supply "expert". I was advised by the "expert" to drain the spa and switch to chlorine, which I did. Now I filled the tub added the metal gone and then later the granulated chlorine. Tested the levels about 3 hours later and WAY too much chlorine. Took a sample to the "expert" and was advised to let the chlorine stabilize for a couple of days before adding any "spa-up or spa-down". Two days later I tested the water, pH normal, Chlorine, does not register. The chlorine side is as clear as the original sample. Like I never added the yellow stuff. Well I am not stupid. No yellow in the cylinder means MORE chlorine. Added more chlorine. Tested 2 hours later, the test results were way to much chlorine. Waited 2 days with no use of the spa and tested again. NO CHLORINE! But the pH is almost ideal. How often should I need to add chlorine to a spa that is set to 103F But is only used once or twice a week? The spa is always covered and has minimal use. Should I ignore the local expert and switch back to the Bromine floater, or do I need to adjust my spa levels on a daily basis even though I use it on a bi-daily basis?? One more question before I end this log winded, very confusing e-mail. I have a nine year old daughter who wants to enjoy the spa with me. I have been told by friends that have spa's that 103°F is too hot for someone her age. Is this correct? If so what is an ideal temperature for a child her age?? Thanks for any help, Cold and confused,

If your pool and spa are separate and do not share common water supplies, I would prefer the use of bromine. It has less odor and allows for easier addition. There is nothing Houdini-like happening! The chlorine or bromine levels drop, if there is organic wastes present, such as after bathing. The test kit that you are using will suffice for bromine use, but it provides inadequate information, when chlorine is being used. I would prefer using a test strip, such as LaMotte Insta-Test, as it furnishes truer data on the state of the sanitizer level. You should test the water at least several times weekly, even if it is not being used. You don't want the sanitizer level to bottom-out, as it will made catch-up more difficult. If you use the floater with bromine, all you should require is pH increaser and, perhaps, a dose of shock after each use of the spa. If you would like assure even better water quality with less work and fewer chemicals, consider adding an ozonator. This will allow the bromine to function in a back-up role and will reduce the chemical sensation. The body mass of your 9-year old daughter is far less than that of an adult. Immersion in 103°F water will cause the temperature of her internal organs to rise more quickly, than that of an adult. Hence, you should lower the temperature, reduce the bathing time, the extent of immersion or all of the preceding. In any case, I would defer to the good judgment of the family doctor or pediatrician. I hope that the information proves helpful. Enjoy the holidays.

Alan, we used bromine in our hot tub but it irritated our skin, in order to switch to a chlorine, do we need to empty our hot tub and start it from scratch with chlorine, or can we just convert over? Thanks.

You must completely drain the spa, removing as much water as possible. Otherwise, the bromide salts, remaining in the spa water will convert the chlorine to bromine. The fact that you described the rash in the plural (we) leads me to believe that the problem may not be the bromine. Bromine tends to less irritating than chlorine. A rash could be the result of too much bromine, too high or low a pH or inadequate spa water sanitizing. If after converting to chlorine, the problems cease: great! However, if problems continue, I suggest that you consider adding an ozonator and reducing the level of chlorine or bromine. The use of a mineral sanitizer or ionizer and an ozonator is a viable option, that utilizes neither chlorine or bromine. I hope this information will solve the problem. Good luck.

My husband and I have been given 2 pieces of advice and wish to find out which one we should follow. At the present time in our Hot Tub we chlorinate and then we test the level and add Bromine tablets to the floater to maintain the chlorine level.. This was told to us by one company. This past month we went to the place we bought the hot tub to purchase needed chemicals and told them what we needed and were told to NEVER use chlorine and bromine together. We have not had any trouble before this advice and were wondering which method of maintaining the chlorine? I would appreciate your advice on this. Thank you.

Cheryl J., 3/15/2007

There is nothing wrong with what you are doing. After bromine has reacted with wastes, it forms bromide ions. Adding chlorine converts the bromide ions back into bromine. Read the label on the bromine tablets. It contains both chemicals and works, as I outlined. What you are doing is maintaining the spa on bromine and using chlorine to shock and that is normal. You should be testing for bromine and trying to maintain 3-5 PPM. If you want to be able to lower the bromine level, add The Spa Frog Mineral Sanitizer. Make sure that you are testing for Bromine. A product, such as the LaMotte Insta-Test Strips, provides the right kind of information and is ideal for this purpose. For more information go to: www.lamotte.com I hope that I have been helpful.

Sincerely. Alan Schuster, 3/15/2007

► Using Bromides With A Salt Chlorine Generator?

We have a 400 gallon hot tub that we sanitize by way of a salt water chlorinator. My question is that if we were to add a product such as sodium bromide to the hot tub, would it convert it to a bromine base versus a chlorine base? Would the salt water generator still work and would it then produce bromine instead of chlorine? I had read somewhere, that if this was done, then you would have to add enough bromide ions as to equal 50 ppm? Is this correct? Any info you can provide on this would be appreciated.

Bob From Canada, 12/18/2008

If you have bromide ions present, the chlorine (hypochlorous acid) will react with the bromides and convert it to bromine (hypobromous acid). This will happen with a salt chlorine generator or any other method of adding chlorine. It will end up as a bromine spa. However, not all manufacturers of salt chlorine generators recommend that their product be used, in this manner. Some are adamant, in their opposition, as it may shorten the life of the salt cell. Apart from AutoPilot, which seems to be able to function with some bromides present, you need to verify the suitability with the salt chlorine generator's manufacturer. There is a specific Bromine Generator product that is intended for use as a bromine generator and is sold on that basis. A 50 PPM level should work, that is if the unit can handle being used with bromides present. You need to contact the manufacturer. Good luck and I hope that I have been helpful.

Sincerely. Alan Schuster, 12/18/2008

► Using Chlorine and Bromine Together?

My husband uses bromine tablets in a floating feeder and uses a chlorine shock treatment in our small hot tub. Is it okay to mix these or should he be using a non-chlorine shock? I ask because sometimes I go into the hot tub and there's an odor that slightly hurts my lungs to breathe and makes me cough. He says bromine and chlorine are the same and it's fine, but I'd like your opinion. Also, how often should you use shock? I think he does it once a week even if the bromine level is fine. Thanks.

Nancy, 10/25/2007

There is nothing wrong with using bromine and chlorine together in the same spa, but they are NOT the same chemical. Bromine tablets actually contain both chlorine and bromide. In the presence of bromide ions, which will come from the bromine tablets, the chlorine will convert to bromine. Adding some granular dichlor is an easy way to boost the bromine level, after periods of heavy bather use or due to low bromine levels. Bromine tablets are acidic and will cause the pH to drop, unless soda ash is added. The low pH is corrosive to equipment and very likely to lead to irritating vapors. Check the pH! You should shock, after periods of heavy bather use, whenever the bromine level bottoms out, at first signs of a loss of water quality or periodically to prevent the buildup of contaminants and resistant microorganisms. The use of a Spa Frog Mineral Sanitizer can reduce the amount of bromine required and provide more consistent conditions. I hope this information is helpful.

Sincerely. Alan Schuster, 10/25/2007

I am using bromine tablets in my hot tub. I work hard at keep the level in the 3-5 PPM and the water seems to be in excellent shape. Do I still need to shock?

Good question! If you add a shock treatment, such as a non-chlorine shock, on a weekly basis or after heavy bather usage or at the first signs of a loss of water quality, you will help destroy the buildup of organic byproducts and help prevent the development of resistant microorganisms. On the other hand, if you rarely shock the water, you increase the likelihood of organic byproducts building up and the development of resistant microorganisms. At the very least, consider adding some non-chlorine shock after periods of heavy usage, in order to quickly re-established the bromine level. I hope that I have been helpful.

Hi there. Just wondering how environmentally friendly bromine is when you empty your spa water containing bromine on your lawn. Thanks.

The other day, while picking up some more bromine tablets, I was browsing the chemical department and came across a product that was 1" chlorine tablets. It contains 90% chlorine and will fit into my bromine floating feeder. It was a lot less expensive. Can this be used?

The bromine tablets that you are using are slow dissolving in your spa. This is important in order to provide a continuous release of bromine into the water. The chlorine product that you described is intended to be used in a swimming pool. This product is slow dissolving, as used in a swimming pool. However, at the temperature of most spas (104ºF), these tablets will dissolve too quickly, making it difficult to control the chlorine and pH. Trichlor is not recommended for use in a spa, in any form. Stick with the bromine -- you'll have less work and less odor. I hope that I have been helpful.

Well, here's the deal. I switch to bromine I never emptied tube I was told no need to. Anyway, I added the bromine tablets to feeder and I added the bromine shock to start a bank as well. got no reading so I shocked it with non-chlorine well that gave me a good dark reading above twenty plus. I did this since the place I brought my water sample to said I needed to break the barrier. I know I got bromine you can smell it now. After the non-chlorine burns off the next day I take a test and it’s a off pink color on a DPD tester I have added tap water to tester as well to see how it brings it down, but color never seems to match the test block really well. I let it go down to the point on tester were there was no color and added more non-chlorine again today and it went back up, but color still off . The place I bring the water to said just let it burn off you will be fine, but, as I said before it goes from a pink to nothing. Can you help? Must be something to get it to look right on tester. It’s a 1000 gal. hot tub Please help.

Find another way to add tablets! Otherwise, you could destroy the heater, if the pH falls into the acidic ranges. Bromine tablets are acidic. Try a floater or a inline bromine feeder, placed after the heater and equipped with a check valve. Depending on bather usage, bromine alone might not be the best solution. Consider adding an ozonator, ultraviolet sanitizer or mineral sanitizer. It sounds like there was a lot of material for the bromine to react with and it may take a day or more for all of the organics to be destroy. Try and keep a bromine level at 3-5 PPM. Unless you added sodium bromide, the chlorine part of the bromine tablets, may take a while to convert to bromine. Bring in a water sample to a local dealer and compare the test results, with your own. Your test chemicals may be outdated or need replacement. Personally, I would prefer using a test strip, such as the LaMotte Insta-Test Strip. High bromine levels can destroy DPD and provide inaccurate results. Under these circumstances, these test strips work best. I hope that this information proves helpful.

We just started taking care of our spas at work. I have a 330 gallon and a 550 gallon spa. We are using bromine tablets in them. The bromine levels seem to be low as the tablets are slow to dissolve, but that is not too much of a concern. My main concern is that the pH is always reading about an 8. I did some research and it said to add a drop of the chlorine neutralizer and that should work, but it doesn't seem to change at all. Also we drain the spa twice a week which is hard to keep the bromine level up. Any suggestions?

I think it is nearly impossible to maintain conditions in a commercial spa, using only bromine. I suggest that you add an ozonator and a UV sanitizer. Otherwise, the bather usage will deplete the sanitizer level too quickly and replenishment will take too long, as the tablets are slow dissolving. If reduced chemical usage is the intent, UV sanitizing is the place to start! UV treatment will reduce the microbial populations in the return flow to near zero, without the use of chemicals. However, it cannot oxidize wastes or totally eliminate the microbial population in pool or spa water or prevent the growth of biofilm on the underwater surfaces. Products such as chlorine, bromine) or non-chlorine shock must be used, in conjunction with UV. How much will be required will depend upon actual bather usage. More usage will require more chemicals. In order to assure that adequate oxidation and sanitation exist at all times, I suggest that you add an ozonator and try and maintain a 3-5 PPM level of bromine. The ozonator will make it easier to maintain the bromine level, by providing oxidation. Bromine will provide the necessary oxidation and sanitizing, while reducing odor. The UV unit will help decrease microbial populations and reduce the amount of bromine necessary to maintain any given PPM level. Over time, charting the amount of chemicals added, the bather usage and the bromine level will provide the best indication of actual chemical requirements. Your pH problem does not seem to be one of bromine interference: the pH seems simply too high. Add the equipment, as recommended, and the water will not have to be changed as often. I hope that this information proves helpful.

Sincerely. Alan Schuster, 1/4/2007

What a great Q&A page. After a great deal of research, your page finally answered many questions. Here is one that has been bothering me. My spa is, overall, NO trouble at all. It uses bromine tabs, has ozone and I shock (non-chlorine) regularly to maintain a +- 2.0 level in the spa. The real question is: what is the practical difference between using tabs which contain dichlor (up to 30% it seems) and using just 96% bromine tabs? Since I am "activating" regularly, I don't seem to see the difference. I realize that bromine requires an "activator", but does it need to be in the tabs? What is your recommendation on the "ideal" management of the spa chemistry? Thanks!!

You seem to have things well in hand. The fact that you have an ozonator, allows you get by with a lower level of bromine. This combination works very well. Once you have an established bromide level, all chlorine or bromine will exist as bromine. The various bromine tabletized products contain various amounts of bromine and chlorine: it all converts to bromide in normal spa use. Using bromine tablets in a floater is very convenient and allows the product to dissolve slowly over time and no additional sodium bromide is usually required. If you use granular dichlor or a tabletized dichlor product, sodium bromide needs to be present in the water, for the chlorine to convert to bromine. It must be added separately, if not present in the product. Bromine has several advantages over chlorine: less odor, less irritation and more flexibility with the pH. The presence of a bromine residual confirms that the ozonator's output and overall maintenance are satisfactory. If bather usage is high, adding some non-chlorine shock will quickly boost the bromide level. I would stick with the ozonator, bromine tablets and non-chlorine shock. I hope that I have been helpful.

I am using bromine tablets and was told that I need to add something to create a bromide bank. Why? What is it? Thanks.

A "bromide bank" means that there is excess sodium bromide present in the water. The bromine tablets actually contain a mixture of bromine and chlorine. As the tablets dissolve, the chlorine will react with BROMIDES present in the water and will be converted into BROMINE. In a freshly filled spa, there are no BROMIDES present. To make sure BROMIDES are present and available to react with chlorine, a liquid sodium bromide solution (The Bromide Bank) is added. This is only done when the spa is freshly filled or refilled. By doing this, there will be none of the odor that can be associated with chlorine usage. I hope that I have explained the product. Enjoy the spa experience.

Hi Alan: I am writing because our bromine levels, that remain steady at 3-5ppm (we have an ozonator), will sometimes jump up to 20+ ppm, after shocking the spa. Both my wife and I are somewhat sensitive to high bromine levels and can't use the spa for at least a couple of days when this happens. We use a float for the Bromine pucks. When the Br spikes, we have to leave the float out to bring the levels down. It does not happen every time I shock the tub. All other water parameters are within range. The water in our area is the hardest in the country, so a lot of chemicals are initially used to bring the hardness down, then the pH up and to get the alkalinity in line. But, once that is done everything remains stable except the Br levels. Any ideas?

Because you are maintaining your spa on bromine, excess mps or chlorine will convert to bromine. When there is nothing for the shock to react with, the bromine level can only go up. The ozonator is doing a lot of the oxidation, so there is no need to shock as often or with a much product. You might only do it monthly, when you don't expect to use the spa. You can quickly drop the bromine level, by adding a chlorine neutralizer product. Use as directed. I am sure that this will explain what is happening, in your spa.

We have emptied and refilled the hot tub twice now and the bromine count still reads almost 20. The second time the alkalinity and pH came into the acceptable ranges, but the bromine is way too high. The tub was emptied due to folliculitis. Is there any other way to decrease the bromine level so it is comfortable to use the spa again. Thanks.

Only two possibilities. Your test kit is not reading properly or you are really adding too much bromine. A level of 3-5 PPM is recommended. The folliculitis could very well have been caused by too little bromine, which lead to inadequate sanitation. Sometimes with bromine there is interference with the pH test. Are you positive that you are reading PPM of bromine? Have you had a dealer confirm these test results? You could be adding too much product at a time. If you are using a monopersulfate shock, it WILL raise the bromine level, as will all forms of chlorine. There is no reason that a refilled spa should have a very high reading, unless too much product has been added. If you have added too much, you can lower the level by adding a chlorine/bromine neutralizer product. As a means of simplifying the sanitizing, you might consider adding an ozonator and a mineral sanitizing system. It will allow you to maintain a low level of bromine 1-2 PPM, with fewer chemicals and afford better water quality. I hope that the information proves helpful. Enjoy the new year.

► Bromine / Sodium Bromide?

Well I think I goofed up big time. I have a spa and read on the internet that after refilling with new water, a bromide bank should be established. I fully understand how it works now I have read this on your Q&A page, but before I discovered your page I was trying to figure out why after adding Sodium Bromide I wasn't getting a Bromine reading. Please note ONLY after reading your page did I even realize here was a difference between BROMIDE and BROMINE. Back to the story: I wasn't getting a bromine reading on the test kit,. so I added more, and more. Still nothing. (Note there is a bromine feeder floating in the spa also). A new pool guy came by and said he doesn't use Sodium Bromide, and instead just crushes the BROMINE tablets and tosses it into the water, to get the thing going and get a reading. So we did that. Well, now the bromine level on the test kit is THROUGH THE ROOF. (I used a total of one pound of Sodium Bromide in about 600 gallons of water. The new guy added about 7 crushed BROMINE tablets.) How do I bring it down?? (the bromine level on the test kit). Do I need to redrain it and start all over again?

The crushing the tablets, as a means of speeding up the dissolution of the bromine will certainly work. But, I would never recommend the practice. The chemical is very slow dissolving. Suppose a bather were to get a speck of the solid bromine in their eye! Not worth the risk. You leaned that a bromide bank is not bromine. Now I am going to tell you that the quickest way to boost the bromine level is to add some non-chlorine shock (preferably a spa formula). This will react with the bromides and form bromine. It is quick and completely soluble. It is possible to lower the bromine level. Many pool or spa dealers carry a product called chlorine neutralizer. Adding this product will eliminate some of the bromine very quickly. Use as per the directions. In the future, remember, you can always add more - you can't take out. I hope that I have been helpful.

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