5 Ways to Prevent Algae Blooms in a Heatwave

Cut off the nutrients Reduce fertilizer runoff, remove leaves and grass clippings, and cut back on fish food. Even small amounts of organic matter can fuel a bloom during a heatwave.

Add floating plants Water lilies or duckweed compete for the same nutrients algae need and block some sunlight. They are a natural, low-effort solution.

Keep the water moving Algae love still, warm water. A pump, fountain, or air stone breaks up thermal stratification and boosts beneficial bacteria that consume nutrients.

Start before the heatwave hits Aeration works best if you set it up in advance. Prevention is easier than cleanup, and a quick rake of debris makes a real difference.

Skip quick fixes unless desperate Barley straw is slow and not a miracle cure. Chemical algaecides can kill fish or crash oxygen levels — use them only as a last resort.