How often should I vacuum my pool to prevent algae?

Once a week is usually enough — but only if you’re also keeping your chemistry balanced. Vacuuming removes debris that feeds algae, but it won’t fix a low chlorine level or a pH that’s out of whack. Brush the walls and floor before vacuuming, and bump it to twice a week in hot weather, after a party, or when leaves are falling. Don’t skip the shocking — a weekly shock does more for prevention than an extra vacuum session ever will.