It sounded like chlorine level went down, so I went to AI to have it explain it more.................Adding pH-down powder (sodium bisulfate) did not cause the algae; rather, your chlorine likely dropped below 1 ppm or your pH had crept high enough before the adjustment to let spores multiply. Salt chlorinators constantly push pH upward, and if sanitization lags, an outbreak hits fast. [1, 2, 3, 4, 5] How to Fix the Green Algae Bloom Brush and Clean: Scrub all pool walls, steps, and floor areas thoroughly to loosen the algae. Clean or backwash your pool filter, as it is likely full of green debris. [1] Adjust pH: Test the water and ensure your pH is balanced between 7.2 and 7.4 so that your upcoming chlorine treatment works at maximum strength. [1, 2, 3, 4, 5] Shock the Pool: Add a heavy dose of liquid chlorine or a strong pool shock at night. Use a double or triple dose depending on how dark green the water is. [1, 2] Run the Pump: Keep your pool filtration system running continuously (24/7) until the water turns a cloudy blue or gray, meaning the algae is dead. [1, 2, 3] Vacuum and Clear: Vacuum any settled debris straight to waste (bypassing the filter), and use a pool clarifier if needed to polish the water clear.
