It sounded like chlorine level went down, as happened to myself before and my daughter's pool also, though not salt water, 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. 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. 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. 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. 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. 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.
