5 Ways to Prevent and Kill Black Algae in Your Pool

Keep chlorine between 1-3 ppm and pH between 7.2-7.6 Test your water weekly. Neglected chlorine levels let black algae take hold.

Brush walls and floor at least once a week Use a stiff stainless steel brush. The physical scrubbing breaks the waxy protective layer that chlorine can’t penetrate on its own.

Shock the pool every seven days during swim season A regular shock schedule prevents algae from establishing. If you see tiny black spots, act that day with a 2x dose of shock.

Skip cheap algaecides They rarely work on black algae. Your best weapons are brushing and proper chlorine levels.

Treat black algae immediately when spotted Black algae plants roots into concrete and forms a protective barrier. Brush aggressively and shock right away. A clean pool is about routine, not emergency fixes.