5 Steps to Remove Black Algae From a Pool

Use a stainless steel or wire brush A soft nylon brush won’t break through black algae’s protective layer. You need a stiff metal brush to scrub hard enough to crack it open.

Scrub aggressively to break the surface Brush the algae spots until the protective outer layer is visibly disrupted. This allows chemicals to penetrate and kill the algae underneath.

Shock the pool with heavy chlorine Apply 2 to 3 times your normal shock dose immediately after scrubbing. Keep chlorine levels elevated for the entire treatment period.

Add a copper-based black algae algaecide Use a dedicated algaecide formulated for black algae. Copper-based products are the most effective option.

Vacuum to waste and repeat the cycle Vacuum the dead algae directly to waste, not through the filter. Repeat the scrub-shock-vacuum cycle three or four times over a week to prevent regrowth.