3 Steps to Kill Black Algae in a Pool

Raise chlorine level Shock the pool to break through the algae’s protective coating. Normal chlorine levels won’t touch it.

Use a stainless steel brush A nylon brush is useless. Stainless steel bristles are required to physically tear the waxy coating so chlorine can penetrate.

Brush aggressively and repeatedly One light pass won’t work. Scrub hard and often until the algae is completely gone.