Hasa Phos Out Phosphate Remover 1 Quart P/N: 77121 HASA PHOS OUT is proven to eliminate phosphates from sources such as fertilizers, cleaners, pool chemicals, and other pollutants. Effective One quart removes up to 1,000 parts per billion of orthophosphates per 20,000 gallons of water. Weekly Maintenance: Use 1 fl. Oz. of HASA Phos Out per 5,000 gallons of pool water to maintain phosphate levels below 125 ppb (parts per billion). Initial high-phosphate treatment: 1. Clean or backwash filter. 2. Calculate the amount of product required using the dosage guide below. Pour Phos Out in the pool, distributing it over as wide an area as possible. Add 1 fluid ounce of HASA Eco-Safe Water Clarifier per 5,000 gallons of swimming pool water. 3. Run your filter system continuously for at least 24 hours. 4. If filter pressure increases 10 psi over normal, clean or backwash filter. 5. After 48 hours test the phosphate level with a phosphate test kit approved for swimming pool use. If it is needed, reapply HASA Phos Out.