4 Things to Know About Phosphates in Your Pool

Don’t test for phosphates unless you have a specific problem Phosphates are everywhere — leaves, dirt, rain, even tap water. Most algae problems are caused by low free chlorine, not high phosphates.

High chlorine and balanced pH prevent algae regardless of phosphates If your chlorine level is high enough and pH is balanced, algae cannot eat the phosphates. Fix chlorine first before chasing phosphates.

Test for phosphates only after ruling out chlorine issues If you have persistent algae despite proper chlorine levels, test with a phosphate test kit or strip. Only consider treatment if levels exceed 1000 ppb.

Treatment is simple but requires vacuuming afterward Use a lanthanum-based phosphate remover. It binds phosphates and they sink to the bottom, so you must vacuum to waste or backwash after treatment.