control and eliminate undesirable foaming, in a
spa or hot tub? 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. Proper sanitation requires that all
foam be eliminated periodically, because the
foam can support a microorganism population and
may not contain adequate sanitizer. If
problems arise, refer to the
Page, as a source of problem-solving
information, broken down into various
categories. Scroll down the page and click on the linked
or images, in the archived answers below, to access additional information, on that topic or product.
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Problem-Solving Information, in a question and
Too much Anti-Foam?
web site and I searched everywhere for a answer
first. And I also asked my spa dealer and a chemical
company and neither bothered to reply. By a stupid
mistake I put way too much anti foam in my spa
tub. It turned the water cloudy and two weeks later
still cloudy. Is my only option to drain and refill?
Thank you for your time. Best regards.
Michael G,, 10/3/2018
anti-foam is pretty harmless stuff and is probably food
grade. Unfortunately, it is an emulsion and cannot be
filtered out. Your best bet is to
drain and clean the spa. Make sure you thoroughly
clean the spa filter, as well.
When adding anti-foam, adding more is not necessarily
going to make it work better. I am sure that this
will solve the problem.
Sincerely. Alan Schuster, 10/3/2018
Alan, You are the only one to take the time to answer my
question. I have asked chemical sellers and even the
place I bought the spa from. You have a customer for
life on any product I need that you carry. Best
► Foam In A Spa?
What causes foamy water in a spa?
What's the best way to deal with the problem?
Ed W., 12/2/2013
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. Water
testing is important and tests, such as calcium hardness and
total alkalinity are also important, in terms of foam
control. I recommend the
ColorQ PRO 7
Digital Water Tester, which does all the
important tests, without color-matching or guesswork. 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.
Sincerely. Alan Schuster, 12/2/2013
► What's In
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.
Klausen H., 1/29/2017
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!
Sincerely. Alan Schuster, 1/30/2017
► A Spa With
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.
Jack l., Erie, PA, 10/25/2016
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 150-250
PPM will help reduce foaming. I hope that I have been of
Sincerely. Alan Schuster, 10/25/2016
Dealing With Foam?
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.
Rick F., Cabot, AR, 6/13/2013
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
200-250 PPM, in order to reduce foaming. Good luck and I
hope that this information proves helpful.
Sincerely. Alan Schuster, 6/14/2013
► Too Much
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
ColorQ tester from your site and I enjoy your insight on spa
John B., Roswell, N.M., 5/28/2011
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
brand, 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
Photometer Test Kit. I hope it serves you well.
Sincerely, Alan Schuster, 5/28/2011
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. I hope that this information will prove
Sincerely. Alan Schuster, 9/25/2006
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., 8/8/2018
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. Draining the spa and starting anew
might be the best option. I hope that this information will
Sincerely. Alan Schuster, 8/8/2018
My spa water has tiny bubbles that
appear when the pump is on. It seems to effervesce like soda
water and disappear when the pump is off. The water appears
to be very clear and there is no noticeable odor. What
should I consider doing, besides changing the water?
David S., 2/23/2008
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.
Sincerely. Alan Schuster, 2/23/2008
Chemistry And Foaming?
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.
K. W., 1/10/2017
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, 1/10/2017
I have foam in my spa and I use a 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?
Steve S., Athol, MA, 3/18/2008
The clarifier should not interfere with the 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.
Sincerely. Alan Schuster, 3/18/2008
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