5 Causes of Foamy Pool Water and How to Fix It

Too much algaecide Most foam comes from overusing algaecide. Switch to a non-foaming type, or apply shock to clear it up.

High calcium hardness Levels above 400 ppm cause foam, especially with aeration from fountains or splashing. Test and adjust with a calcium reducer.

Phosphate overload Phosphates from leaves or fertilizers feed algae. When chlorine kills the algae, dead cells create foam. Use a phosphate remover.

Organic residue buildup Shock the pool to break down oils, lotions, and other organic matter that can cause foaming.

Using defoamer as a permanent fix Pool defoamer knocks foam down in minutes, but it’s a bandaid. Fix the root chemical imbalance or the foam returns.