Hot Tub Life
Spa Water Foam Problems
the November 1998 Edition of the Hot Tub Life Newsletter
Dear Spa Guy:
I keep getting disgusting
white foam on the top of my hot tub water. After I refill the tub,
the water is great for about 4 weeks, then the foam starts.
Gradually after a few more weeks, it gets so high that I cannot see
my husband any more through the foam. What causes this and how can I
get rid of it ? - Foamy in West Hampton, NY
Hot tub water foam is caused
when the Total Dissolved Solids (TDS) level in the water build up
and are brought to the water surface by either the use of the air
bubbler (blower) or the air being injected through your jets. The
dissolved solids in the water sort of "stick" to the air
bubbles coming up through the water and are brought to the surface.
You see this as "foam". The foam is actually the dissolved
solids clinging to the air bubbles as they escape upwards into the
air. The foam is the "stuff" that was previously dissolved
in the water.
TDS levels can build up in the
water from many things. When you get in a hot tub, a lot of
unpleasant stuff comes off of you. Perspiration, dead skin
cells, underarm deodorant, soap residue and dirt from bathing suits,
skin lotions and creams, hair spray, etc. Some of this microscopic
stuff is caught by your filter, but a lot of it simply dissolves in
the water. Also, every time you add any type of chemical to the
water, you are introducing additional solids into the same body of
Depending on how much of these
items are put into the water, and how fast (days, weeks, or months),
this will determine the point at which your water becomes saturated.
Once that starts to happen, the first thing you will see is the
foam. Soon thereafter, the water will permanently cloud – as it
reaches its true saturation point of TDS’s.
Once that happens, no amount
of filtering or additional chemicals will clear the water and you
will have to change it. Water Defoamer will help combat foam
for a while, but your best bet is to be as clean as possible before
going into the tub. That way you should be able to get about 8 weeks
between water changes.