spa water foaming problems: controlling problems with spa water foaming

Foaming and scum formation are serious detractions from the goal of crystal clear spa and hot tub water. Spa chemicals generally do not cause foaming, although biguanide can cause some low level foaming. The most common cause is the reaction of body oils and cosmetic residues with the natural alkalinity of the water. This can lead to the formation of "soaps" and the possibility of a foamy water problem. While an anti-foam can help, the problem may recur. Foaming spa water can be controlled and eliminated with the use of Enzyme Products and avoiding "soft" water conditions. 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.

More information about the ColorQ Water Analyzers can be found by clicking on the above image. This hand-held, digital tester requires no color matching or look up charts and performs the following tests: pH, Free & Total Chlorine, Bromine, Total Alkalinity, Hardness and Cyanuric Acid. Be better informed and avoid costly problems!

Bathers contribute body oils to the water, as a result of the warm water. These body oils can react with the natural alkalinity of the water and form "soaps." Add aeration and you get foamy spa water. You can use a spa formula Anti-Foam Product to help break the foam. An Enzyme Treatment can be added periodically, in order to digest or decompose the body oils and prevent the formation of these "soaps." Soft water will support more foaming. Keeping the calcium hardness level in the 150-200 PPM, can help suppress foaming. It is important to completely eliminate all foam, for some period of time. This is necessary, in order to assure proper sanitation, because the ecology of the foam is different from that of the water. I hope that I have been helpful. Enjoy the spa.

Alan, great site, I immediately added you to my favorites. One question regarding spa anti-foam solutions: all other products I use list their active and inert ingredients and % on the label, but not so with anti-foam products. Can you tell me more about the chemical is that is typically used, the %, etc, so I can look up the MSDS info, as I have done for Potassium Peroxymonosulfate, for example. Thanks.

Anti-foam products are not pesticides and, as such, do not require that same type of ingredient disclosure, that is required of products such as chlorine or algaecide. At least not in the U.S. The various products, currently on the market, are not necessarily all based upon the same formulation or have the same activity content. Virtually all spa antifoam products are based upon a silicone oil in a non-ionic emulsion. The silicone content will vary depending upon the packaging and marketing strategy. A 10% silicone content would be a reasonable ballpark figure. These products are used a very low levels and have a low order of toxicity. In a spa, the elimination of all foam, at least periodically, is important for proper sanitation. If you have an ozonator, it can help reduce the foaming problem, by breaking down the foaming materials. I hope that I have been helpful. Enjoy the spa experience!

Sometimes my spa gets so much foam on top it looks like a head on a beer. I use bromine tablets and non-chlorine shock. I never use fragrances or other similar products. So which chemical is causing the foam? Thanks a lot.

Actually, none of the chemicals are responsible. Body oils from bathers, react with the natural alkalinity of the water and form "soaps." The air jets create the foamy water. It is important for good sanitation reasons to eliminate all foam, at least temporarily. Foaming can be controlled with additions of anti-foam products. Enzyme products can help eliminate the body oils and reduce "soap" formation. If your spa water is soft, raising the calcium hardness to 150-200 PPM will help reduce foaming. I hope that I have been of assistance.

I know you thought you were through with me, but I still have a little issue with foaming. The spa I own has 4 pumps. On each of these pumps is a feature called therapy jets that increases the pressure of the water coming from each pump. When I run pumps 1, 3, and 4 without the therapy jets, there is zero foaming in the spa. But if I turn on pump 2 or add the therapy jets to any of the pumps, the spa foams. I've drained and refilled and this still happens. The water is sanitized correctly, I use the stain and scale preventives and water clarifiers the manufacturer recommends, and it has the correct hardness. Now what is happening to the spa? Thanks.

The foam is mostly likely being caused by the reaction of body oils and/or cosmetic residues with the natural alkalinity of the water. This causes the formation of soaps. Try adding a weekly dose of an enzyme to help digest these byproducts. Make sure that the calcium hardness is about 200 PPM, in order to reduce foaming. Good luck and I hope that this information proves helpful.

Alan, please help on a few issues I'm having with my spa. My son brings his friends over and my spa turns into a bubble bath. Besides changing the water out, what gets rid of soap and how fast does to work? Also, I live in the southwest where we have hard water and I've been thinking of switching to soft water. But, a friend I know uses reverse osmosis water and he has a lot of white scale on everything. What is the white scale in his water and would that help the foaming? Also, why can't you use bromine with a mineral filter or cartridge. I've bought a tester from your site and I enjoy your insight on spa problems. Thanks.

This "soap" is the product of body oils reacting with the natural alkalinity of the water. Increased numbers of bathers and prolonged bathing sessions can add to the magnitude of the problem. Soft water actually increases the foaming problem and high pH increases the soap formation. Very hard water, on the other hand, can result in soap scum formation. Adding anti-foam will temporarily eliminate the foam. Incidentally, good sanitation requires that all foam be eliminated from time to time. Adding an enzyme treatment periodically can help digest the body oils and reduce the soap formation. The presence of an ozonator can help destroy the body oils over a period of time and it turn can lessen the foaming. It would be a very worthwhile addition, if you don't have one. So far as I know, mineral sanitizers can be used with bromine, with the exception of one particular product, as bromine will drastically shorten the life of their cartridge. I hope that I have shed some light on the subject. In short, limiting the bather load, adding enzymes, controlling the hardness and using an ozonator, should help produce less foaming. Thanks for the purchase of the Colorimeter Test Kit. I hope it serves you well.

We have a new (2 month old) spa that holds about 250 gallons. We use it every day - sometimes twice a day - two adults. It has an ozonator, an ionizer (silver) and we used MPS as a sanitizer. In the last two weeks, it developed a cloudiness. I used additional MPS - 3 tablespoons - and it cleared up. I usually add at least a tablespoon of MPS each day. Now it has developed a sort of scum floating on the surface of the water. The filters have been cleaned and replaced. Does this suggest to you that it is time to empty the spa and start all over again?? All of the test readings are adequate. FOR YOUR INFORMATION, I AM HIGHLY ALLERGIC TO CHLORINE - SO WE CAN'T USE ANY CHLORINE IN THE TAB AT ALL. Do you have any suggestions? Thanks.

S. H., 9/25/2006

The addition of the MPS and the clearing up of the water, suggest that the ozonator output is not adequate to meet the demands of your spa. This is a heavy use situation, given the frequency of use and the smaller size of the spa. You probably should replace the water more often than every 3 months, as is usually recommended. I would add extra MPS, after each use and try and confirm that the ozonator is working properly. Use it for at least 3 or 4, 2-hour sessions daily. Adding an enzyme treatment could help digest this floating scum. You can also improve filtration with the addition of a MicroPure disposable spa filter. I hope that this information will prove helpful.

We have a new 500 gal spa. Our new home has very soft water (hardness 85) and this seams to be a problem. I have kept a handle on the chemicals (bromine) but seams that after 3 week of very little use (2hrs) the water is clear but when the jets are turned on the water turns white and foams. I noticed that after I used an algaecide it began to do this, but I only added very little. I add calcium to boost the hardness level and wonder if it needs other minerals. I have contacted several places but no one has the answer or if the lack of chemicals in the water is the problem. It has become a pain and I'm almost ready to sell it. HELP

Nancy H., 8/8/2006

Spa water that is soft is more likely to foam. Raise the hardness to about 200 PPM, by adding a calcium hardness booster. Antifoam can be used to help control the foaming. Algaecides are not normally used in spas. If the product you added contains dimethyl benzyl ammonium chloride or something close, it should not be added again. This type of algaecide will cause foaming, even in a pool. An aerated spa makes it much worse. With proper sanitation, there is no need to add an algaecide. I hope that this information will prove helpful.

Changing the water, may not be the solution. Normally, water is replaced every three months, on average, more or less depending upon usage. It is probably carbon dioxide gassing off. Make sure that the pH and TA are in range. Adding a sodium borate product will help maintain the pH and TA and help prevent carbon dioxide from dissolving in the water. The bubbles might be forming as the temperature changes. If you have an ozonator, it does aerate the water, as a means of delivering the ozone. If you use biguanide, foam problems are unavoidable. I hope this information proves useful.

I have been working on getting my spa water in correct chemical balance. What causes foam in the water? My alkalinity was low and my pH was at the upper end of the range. I increased the alkalinity and decreased pH. I now have foam. What gives? Thanks.

Foam is promoted by "soaps" that are formed by the reaction of the natural alkalinity of the water and body oils and cosmetic residues. High pH and TA can make it happen more quickly. Aeration and high water temperature make it all occur. Good sanitizing practices demands that at some point all foam be eliminated. Defoamers are very efficient. More is not necessarily better! They work, but are temporary. There are things that you can do. Have the water tested for calcium hardness and raise the level to 200 PPM. Hard water is less likely to support foaming. In addition, add an enzyme treatment to the water, as this type of product will help digest the body oils and cosmetic residues that lead to the formation of soaps. Anything that you can do to reduce body oils and cosmetic residues would be helpful. I hope that this information proves helpful.

Sincerely. Alan Schuster, 1/10/2007

I have foam in my spa and I use a Spa Frog mineral sanitizer. I was told to get a clarifier to use and that will work to get the foam down and in the filter. I shock it after every use and one and a half oz. every Friday. Will the clarifier hurt the mineral sanitizer?

The clarifier should not interfere with the Spa Frog mineral sanitizer. Adding it weekly can help eliminate organic debris and improve water clarity. However, there is really no basis for adding a clarifier to control foaming. Foaming is the result of soap formation, caused by body oils and cosmetic residues reacting with the natural alkalinity of the spa water. Foaming can be temporarily controlled by the addition of a spa-formula antifoam product. Check the calcium hardness and boost it to 200 PPM, if the level is low (soft water). Hard water makes foaming more difficult. The addition of an enzyme product, on a weekly basis, will help digest oily residues and help eliminate the soap formation that leads to foaming. Enzyme products are safe to use with mineral sanitizers. I hope that I have cleared things up a bit. Enjoy the spa.

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