spa water analysis-chemistry-testing: help with spa water analysis-testing

Scroll down to browse through some archived SPA & HOT TUB questions and answers. Please access the Spa Topics Page and other links, at the top of every page, for additional information.

Proper water management starts with the analysis and balancing of the spa or hot tub water. Tests such as pH and sanitizer need to be performed by the spa owner, on a frequent or daily basis, depending upon the sanitizer choice and usage conditions. If Chlorine is used, it should be tested by a method that measures Free Chlorine, as it is the most important. Tests such as total alkalinity and calcium hardness are performed occasionally and can be done by a spa owner or dealer. Tests for heavy metals such as iron, manganese or copper should be performed at the initial filling or at the first indications of spa water discoloration or a spa surfaces staining problem. These tests are usually performed by a spa professional. Maintaining or balancing proper spa or hot tub water chemistry is important to help assure optimum water quality and to maximize the "hot water" experience. 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.

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► Choosing A Bromine Test Kit?

My hot tub is on the 2-part bromine system. What is the best way to test for bromine. Can I use a swimming pool test kit? I see a lot more of the test strips around these days. I've never used them. Are they reliable? Thanks for any help you can offer.

Vicky S., Coconut Creek, FL, 2/4/2004

I would not suggest that you use a swimming pool test kit, unless it is specifically made to test for bromine! Bromine can interfere with the pH test and give a false high test result, if the pH test materials are not formulated properly. Test strips have come a long way in terms of reliability, accuracy and the number of different tests that can be performed. The majority of test strips can test for chlorine and bromine and the convenience and lack of liquid chemicals makes them a choice of growing popularity. Browsing through the archives on this topic might be a good idea. Glad to help.

Sincerely. Alan Schuster, 2/4/2004

► How Often To Test Spa Water?

Everything that I read seems to give a different answer to the question of how often spa water should be tested. What's your take?

Alec, Marlboro, NJ, 9/23/2005

There is a lot of subjectivity on this topic. My feeling is that it is better to test more often than less often! I suggest that the sanitizer level and pH be tested prior to each use of the spa. If the sanitizer level is too low, it should be adjusted and at least 1/2 hour should be allowed to pass before the spa is used. In addition, I would test the spa after each use. This will allow the sanitizer to be replenished on an as needed basis, decreasing the possibility of bacterial growth between uses of the spa. If the spa is only used occasionally, it should be tested at least weekly, just to make sure that the sanitizer level is being adequately maintained. The proper balancing of spa or hot tub water will, in the long run, avoid many problems. At least occasionally, to better assure proper overall spa water chemistry, visit a pool/spa store that has a very reliable, professional lab such as a WaterLink or Pinpoint system, rather than a less accurate test kit or strip reader. To locate a dealer near you, go to: www.lamotte.com/pages/pool/expdeal/index.html I hope that I have shed some light on the subject. Enjoy the spa.

Sincerely. Alan Schuster, 9/23/2005

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► Proper Sampling For Test Strips?

How is it best to sample the water, when using test strips?

Chad, New Jersey, 1/4/2004

While is good practice to test the water before using the spa and afterwards, how the water is sampled is important. Follow the manufacturer's instructions! Always shut off the pump and never immerse the test strip in front of a moving jet. To do so might wash the chemicals out of the test strip and give false readings. I hope that I have been of help.

Sincerely. Alan Schuster, 1/4/2004

► Which Test Strips To Choose?

I have been using test strips ever since I got the hot tub about 2 years ago. They seem to do a pretty reliable job. I have been using bromine, with an Ozonator. I have seen another brand of strips that are much less expensive. Are they as good? Thank you.

Ed M., San Jose, CA, 4/23/2003

I don't want to say that the other strips don't work because I don't know anything about them. But this I do know! Test strips are not simply chemicals on paper. Test strips, for spas, hot tubs and pools, grew out of the medical testing industry: where they were developed to run certain blood and urine tests. Some pretty sophisticated technology is involved - even in test strips for this industry - in order to produce testing materials that can provide accuracy, reliability and have a reasonably long shelf life. Not all of the strips out there meet this standard. Sometimes, even a thing as simple as how they are packaged can make a big difference. Test strips must be protected against moisture, in order to maintain their reliability and shelf life. While all test strips may have a drying aid inside to help absorb moisture, the LaMotte Insta-Test Strips have included a more effective, moisture-absorbing, desiccant liner in the package, for added reliability and shelf-life. Because so much depends on the accuracy and reliability of the test results, I would stick with the brand that has gained your confidence and satisfaction. When using test strips always remove the strips with dry hands and reseal promptly. Keep the unused strips away from heat, moisture and light. I hope that I have been helpful. Please browse through the archives on this and related topics. Enjoy the hot water experience.

Sincerely. Alan Schuster, 4/24/2003

► UV, Ozone And Water Testing?

I ordered 3 or the LaMotte ColorQ PRO 7 digital meters, from your website, a while back. Don't know if the results would approach laboratory standards, but it's far more accurate than the old eye interpretation. LaMotte has outdone themselves. And it's so easy to use! The 2 biggest problems I see are it may be better in a water tight (or close to) case, but mainly more people need to know about it. Do you spend much time marketing these things? I think they would sell well, if more folks knew about them. But, the real question. Still playing with well water . Going to add Chlorine by injection. Had bought and was gonna install an ultra-violet light. Don't need it now. Has anyone reported on its use or is it just a plain stupid idea to put it in my hot tub? I sure can't notice a difference with the hot tub ozonator. In your spa book, you mention filling the spa with softened water. I couldn't agree more. And with the help of the LaMotte ColorQ, I now know how much calcium to add. Thanks for the books and meters.

Rodger P., Tampa, Florida, 2/19/2008

Thanks for the purchases and your comments. Sales of the ColorQ Water Analyzer, and the new additions to the line, are going well. My website reaches a considerable number of people, but there are lots more out there. With a price of only $129.00 and the capability to perform 7 different pool or spa water tests, I think the handy case does what is required: organizes and keeps everything in its proper place. Word of mouth seems to play a big factor, as I am on so many favorites lists, according to many of the writers. UV sanitizers make a lot of sense, especially, if you understand their limitations. While it kills virtually everything, in the return flow, including some of the worst microorganisms, it cannot be used alone. You need oxidation, such as chlorine, bromine or an ozone generator. Even if you add an ozone generator, you might not kill all the microorganisms on the underwater surfaces. That is where chlorine and bromine come into play. If your ozonator is working properly and is used for enough time, it will reduce the required amount of, chlorine or bromine, to a fraction of what it would be, otherwise. With the proper use of UV and ozone, almost any measurable level of free chlorine will suffice. The system is redundant and should not be subject to rapid bacterial growth. The problems begin, when people try and eliminate all of the chlorine or bromine. Minimizing should be the goal. And you have the ColorQ to do the testing. While an analytical laboratory could produce more precise answers, it would be overkill. The ColorQ provides all the accuracy a pool or spa test requires, while maintaining simplicity and ease of operation. I hope this information is helpful.

Sincerely. Alan Schuster, 2/19/2008

► Color Blind?

I would love to be able to test my spa water, but I am color blind. I have to keep after my wife to read the test strips. We have an ozonator and the dealer suggested that we maintain a 1-2 PPM chlorine level. I can't read the chlorine or pH colors, so is there any other way to test the water?

Bill J., 2/17/2005

Help has arrived. The LaMotte ColorQ are a group of hand-held, colorimeter than you can use to test for Free & Total Chlorine, pH, Alkalinity, calcium Hardness and Cyanuric Acid. Some models test for biguanide, biguanide shock, copper and iron, as well as some or all of the other tests. One will be right for you. It is done simply, quickly and without having to look at any colors or look up charts. Just read the answers on the LCD Display. The price is reasonable and it will put you in complete control. For more information on this product go to: www.lamotte.com The proper testing of spa water helps to make the hot water experience a more pleasurable one, by helping to improve water quality and sanitation. I hope that it works out for you and that the website was helpful.

Sincerely. Alan Schuster, 2/18/2005

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► Can Lighting Affect Readings?

The spa water test readings, seem quite different, viewed in the spa area (Commercial Spa), with the sodium vapor lights. When I go into an area with regular lighting, the colors seem different. Is it because of the color of the light? Thanks

Laura. R., 10/1/2007

The color of the light could be the problem. Test strips and comparator colors can be influenced by lighting and sodium vapor lights are probably the most troublesome. Any colored or dim lighting can be a factor. It is best to read under bright natural light or white lights. One way to avoid all of these problems is with the LaMotte ColorQ Water Analyzers. There are several models and one would be right for your situation. I hope that this will help provide more consistency and help solve the testing difficulties..

Sincerely. Alan Schuster, 10/2/2007

► Spa Test Kit?

I have been using dichlor in my hot tub and have been using test strips. They seem to be labeled for pools or spa and chlorine or bromine. Is there a problem using this product? Thank you.

Mike, Summerlin, NV, 1/9/2003

Works for me! Because you are using chlorine, it is important to test for Free Chlorine: the active sanitizing form of chlorine. This is more important than Total Chlorine. So long as the Test Strips measure Free Chlorine, I don't see a problem. I would not recommend that you use an OTO test kit. Try and keep the Free Chlorine at 1-3 PPM. The Total Chlorine reading should be no more than 1-2 PPM higher, at most. If the Total Chlorine is much higher, you might have to shock: a non-chlorine shock should be effective at converting the combined chlorine into Free Chlorine. Don't forget to test for the pH on a daily basis and the TA and calcium hardness on a regular basis. This will help keep the spa water chemistry in balance and help maintain proper water quality and clarity. Enjoy the hot tub.

Sincerely. Alan Schuster, 1/10/2003

► Bromine Test Turning Orange?

My hot tub holds 300 gallons and the water has only been used 2 times since it was changed. The temperature right now is 102 degrees. My chemical test kit is giving me a reading of 7.5-7.6 pH and Alkalinity in the normal range. However, my bromine test result is a dark, burnt orange. I have had the hot tub for 2 years and never encountered this before. What is the problem? Too much Bromine? What do I need to do to correct? Do I have to change the water again? The bromine in my floater seems to be dissolving faster than ever. Please advise. Thank you so much.

Jen G., 4/1/2007

This sounds like you are using an OTO test kit and that the bromine level is very high. I suggest that you mix 4 parts of tap water with one part spa water and test immediately. Multiply the answer by 5. A better way to test water would be with the LaMotte Insta-Test strips, as they perform best with high chlorine or bromine content. Scale back on the amount of bromine being added. You might replace some water to lower the bromine level, if water has not been replaced recently. Otherwise, there is a bromine neutralizing chemical that you can add. The addition of a Spa Frog mineral sanitizer is something that you should consider, as it will make maintenance easier and produce higher quality water. It will reduce the chemical consumption. All you should need is a very low level of bromine, 1-3 PPM. I hope that this information is helpful.

Sincerely. Alan Schuster, 4/2/2007

► Added No Bromine?

Excellent website, very informative for the "chemistry challenged" people like myself. Hoping you can help? We just purchased our spa within the last month and were given starter chemicals: dichlor, shock, test strips, pH buffer. These are the only chemicals we are using. The original test strips tested for Chlorine, Total alkalinity and pH. When I ran out, I purchased a different brand of test strips that also happened to test for bromine besides chlorine. Now these test strips are testing positive for both Chlorine and Bromine, although we don't even own any Bromine chemicals. I went to have water tested where we purchased the spa and received the same results. They too were puzzled saying that it shouldn't show positive for Bromine but didn't seem concerned. Any suggestions? Also while there, they said that our pH was too low and that we needed to add more chlorine which I did yesterday. All readings are now very high. I am showing 5 for Bromine, 5 for Chlorine, 180 for TA and 8.4 for pH. Should I be concerned or will the pH lower itself? Thanks

Barbara, Bloomfield NJ, 6/10/2004

The test methods for chlorine and bromine are, basically, the same. It is the color comparison charts that are different. You did not add bromine and, therefore, you should ignore the bromine reading. There is nothing to be concerned about, just maintain a free chlorine level of 1-3 PPM. The pH of 8.4 is too high and should be lowered. A high pH will reduce the effectiveness of chlorine and could prove irritating to bathers. A pH of 7.2-7.6 is recommended for chlorine maintained spas. Enjoy the spa.

Sincerely. Alan Schuster, 6/10/2004

► Are The Devices Working?

Great site for info. We have recently purchased a hot tub and tried chlorine, then bromine with little success. The hot tub has an ozonator and we bought a mineralizer to use in conjunction with ozonator, hoping to reduce greatly or eliminate chemicals like chlorine & bromine. Problem we have, is knowing whether the devices are working, as the test strips are for the chemicals. Would appreciate any info on ways to test the devices or water to be sure THEY ARE WORKING. I should add that we drained, cleaned and refilled tub when we installed purifier and now back to chlorine daily & non-chlorine shock weekly. Thank you very much for any help.

Joyce S. in New York, 2/10/2005

Sounds like you have tried everything. The problem is that you that didn't mention if you actually had problems. You should be able to get ideal water quality, by using the ozonator and maintaining a 1-3 PPM level of bromine. There should be little chemical presence. Make sure that the ozonator is operated for at least 4-2 hour periods, spread throughout the day. This will provide the necessary oxidation of waste products and make it easier to maintain the bromine level with fewer chemicals. There's no problem testing for bromine: test strips are fine. The ability to maintain a satisfactory level with a minimum use of bromine can be taken as confirmation that the ozonation is proper. When the cover is removed, you might be able to smell ozone: the scent of crashing waves? Ozone test kits are available that can be used to test for ozone. For information click here. You should not require chlorine or a mineral purifier. MPS should only be added, if there is a loss of water quality or after periods of heavy bather usage. Adding a small amount of MPS, after each use, will help restore the bromine level. It just seems a matter of putting some trust in the test results and your own observations. The water should be clear and there should not be any slimy film on the underwater surfaces, as these are signs that sanitation might be inadequate. I hope that this information helps to put your mind at ease. Enjoy the spa.

Sincerely. Alan Schuster, 2/11/2005

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► Testing For Ozone?

I have a spa (500 gal) equipped with an ozonator and silver ion cartridge in the one filter. I shock the spa about once a week with two tablespoons Sodium Dichloro-S-Triaznetrione Dihydrate and add 2 tablespoons of MPS before or after each spa use. The spa is one year old. About six months ago, I stopped smelling ozone and the dealer replaced the ozone generator. I smelled ozone strongly for about 5 months whenever I took off the cover, but suddenly it stopped again about two months ago. I decided to purchase an Ozone test kit and have the LaMotte Model EC-63 (Code 3547) which I used today and got a strong positive reading. But I am wondering if that might be a false test due to the presence of other oxidizers (Cl2 and MPS). Before I get the dealer out here again, can you tell me if it is likely these other oxidizers gave a false reading? If so, what might I do to actually test ozone output? Thanks very much.

Owen G., PHD, Florida, 8/24/2004

The kit should indicate that oxidizers can interfere. DPD will react with the Dichlor and MPS remaining in the spa. There more sophisticated and expensive methods to test Ozone, in the presence of other oxidizers, but they involve a colorimeter with indigotrisulfonate. If the chlorine and MPS are allowed to dissipate to zero (MPS won't take long), then a sample can be taken near the outlet to capture an ozone reading. Basically leaving the spa uncovered a day or so, could get the chlorine level down to zero. Verify the result is zero, then without adding any chemicals, make sure that the ozone generator is operating (pump should be on low speed) and take a test. If ANY color shows up the ozonator is operating. I hope the information proves helpful.

Sincerely. Alan Schuster, 8/25/2004

► Bromine Or Chlorine?

Hi Alan. My spa chemicals came with test strips. The readings are Bromine levels, Free Chlorine levels, pH, and TA. In a Bromine sanitized spa, is there supposed to be free chlorine? If so, my other readings are all good, but there's never any free chlorine. What should I do? Thanks.

John M., 11/16/2003

The same test strips are used to test for either chlorine or bromine. In a bromine-maintained spa there is no chlorine present - it's all bromine. You should disregard the chlorine readings, as they are meaningless, in your case. Enjoy the spa!

Sincerely. Alan Schuster, 11/17/2003

► Difficulty Testing pH In A Biguanide Spa?

Alan, I use biguanide for the spa and their test strips. For some reason I find the results hard to read. Especially pH always appears high, but when I have had the water tested at the spa dealer it appears to be in the correct range. Is there another test strip or kit I can use for the biguanide system that will test pH, TA, Hardness, Sanitizer? I have had problem with calcium & high pH that resulted the circulation pump going bad. Thanks for your assistance

Jeff Y. Bonita Beach, FL, 12/27/2007

The strips are convenient, but some are not as good as other test methods, when used in a biguanide-maintained spa. The more traditional testing materials, used prior to the test strips, seemed to provide good results and are probably still being used by the dealers. For a better testing option consider using the ColorQ Biguanide PRO 5 Water Analyzer. It is all-digital, requires no color matching or look-up charts and it's affordably priced. In addition to testing for biguanide, it performs the pH. total alkalinity, calcium hardness and Biguanide Shock tests. It is the perfect tester, for those with any color vision impairment. I hope that this information will prove helpful.

Sincerely. Alan Schuster, 12/27/2007

► Need To Replace?

I think that I goofed. I was actually in my spa, when I reached over and grabbed the test strips. I may have gotten a drop or two of water on the strips. Can this cause a problem?

Ron S., 1/5/2005

It is a real probability. The test strips are usually packaged with a drying aid inside. This is done to help protect against the deteriorating effects of moisture. Always remove test strips with dry fingers, reseal the container and store away from light, moisture and heat. There is no way for me to determine, if the strips are still reliable. Most test strips have expiration dates and are packaged in quantities that make regular replacement routine, if the spa water is being tested on an appropriately frequent basis. To be safe, replace all testing materials at least yearly or whenever something appears different. I hope that I have been of assistance.

Sincerely. Alan Schuster, 1/5/2005

► Spa Chlorine Test Kit?

My spa came with a test kit that uses 2 liquids for the pH and chlorine test. What is the best test kit to use with my spa? I am running out and need to but replacements. It is 275 gallons and I use sodium dichlor. Thanks.

Andy M., CA, 1/6/2003

If the test kit that you are using contains OTO for the chlorine test, it is not one that I would recommend. It is important that you test for Free Chlorine and OTO cannot do that. I suggest that you use either Test Strips or a DPD Test Kit that is labeled for chlorine use. These products will probably test for both Free and Total Chlorine. In either case, you'll be much better off, than with an OTO Test Kit. I hope that I have been helpful. Please browse through the archives for more on this and related topics. Enjoy the spa.

Sincerely. Alan Schuster, 1/6/2003

► pH Challenged?

I have realized that my key challenge with my spa is pH. Unfortunately, the traditional test strips are difficult for me to read. Are the pH testers in your store really more accurate? What else would I need to order in addition to the tester itself?

Chris N. Reno, NV, 11/1/2006

Some people do seem to have color perception problems and for them an electronic tester is just what is needed. The LaMotte ColorQ Water Analyzer tests for pH, free and total chlorine, total alkalinity calcium hardness and cyanuric acid. The kit includes everything and there are no colors to match and no look up charts! The test results come right up on the digital display. The instrument is hand-held and perfect for spa or pool side use. Accuracy is better than most other test methods. I hope that this information proves helpful.

Sincerely. Alan Schuster, 11/1/2006

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► Wrong Test Strips?

Thanks for your quick reply. I think you may have misunderstood me in my question just a little. I already added the baking soda to raise total alkalinity and pH, as my pH was reading 7 according to the strip I was using. This strip was called pHydrion Vivid 6-8. They weren't meant for hot tubs, but figured they should read the same. I understood most of what you suggested but was wondering if my readings were artificially high being that I took my water sample to the spa store only 20 minutes after adding the baking soda? Is muriatic acid ok to use as I have some already? If it is could you suggest amounts? Thanks again.

Darren H., 4/21/2005

You're right, I did misunderstand you and I wasn't aware of what you were actually describing as a test strip. You are not using a test strip, at all. You are using an industrial pH paper that is only intended to be used as a ballpark figure and not to test pool or spa water. That's why there was no agreement with the pool store. I suggest that you use pH reducer granules. If you insist on using muriatic acid, add no more that a few ounces at a time and retest with an appropriate spa tester: something like the LaMotte Insta-Test strips would be ideal. Remember, you can always add more -- you can't take out! I hope that I have been helpful and help set the record straight.

Sincerely. Alan Schuster, 4/21/2005

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