Nylon brush, mild algaecide, and patience

Yes, scrub with a nylon brush and a gentle algaecide — that’s your safest bet.

Wire brushes or stiff bristles will scratch plaster, chip fiberglass, and tear vinyl liners. You don’t need that kind of aggression. A good pool wall brush with nylon bristles costs about $20 and does the job without damage.

For stubborn spots, use a pumice stone (the kind for pool tiles) while the surface is wet. Rub gently. No steel wool, no pressure washer, no bleach scrubs.

The real trick is preventing the algae in the first place — keep your chlorine and pH balanced, and brush weekly. But if you’re already dealing with it, go soft and be patient.

Your pool finish will thank you.