White water mold is not common, but it occasionally appears in mid-south pools and spas. It most commonly attacks water that uses products such as Baquacil, but it can also appear in chlorinated and salt water pools. It’s often referred to as “bio-slime.”

White water mold appears as a stringy, slimy substance that floats in the water and/or attaches to the pool’s walls. In the water, white water mold looks like white mucous or a tissue paper substance. The mold will attach to baskets, even cause them to clog. The mold can grow inside the plumbing system, the filter, and even a garden hose.

Another form of this has a pinkish appearance; thus, it is sometimes referred to as “pink algae.” If some green algae is present, the mold may take on a greenish appearance. Actually, this mold is not an algae form.

White water mold and pink algae is very resistant to many chemicals. Traditional algaecides have no effect on the mold. Pools and spas using biguanides such as Baquacil should consider converting to chlorine. Otherwise, they should check with their dealer for treatment recommendations.


The most effective treatment is similar to treating mustard algae but requires much heavier chlorine shock dosages as follows:

  1. Make sure pH is adjusted to 7.0-7.4.
  2. Add one 6-ounce package of Yellow Out for each 15,000 gallons.
  3. Add 6 pounds of Poolife Turbo Shock for each 15,000 gallons. Add some through the skimmer to treat the plumbing lines and filter system.
  4. Add 1 quart of Muriatic Acid or 2.5 pounds of pH MINUS for each 4 pounds of Poolife Turbo Shock added.
  5. Add 4 ounces of Pool Baron's Ultra Clarifier for each 10,000 gallons.
  6. If you have a cartridge or D.E. filter, the filter should be opened and cleaned.
  7. Operate the filter continuously (24 hours a day).
  8. 8. Remove all floats and toys from the water and wash. Allow to dry in direct sunlight.
  9. 9. If there is any “slime” remaining after 48 hours, another treatment of equal amount is required.
  10. 10. After mold or pink algae is killed and water is clear, increase your chlorine feed for a few weeks since Pool Baron's Yellow Clear deactivates the effectiveness of chlorine stabilizer.
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