Pool Mate Algaecide 50 is an excellent all-around algaecide treatment. Keeps pool water free and sparkling, clear of visible green and blue green algae, slime and green brown colors. A 50% quaternary algaecide, this product prevents algae formation, destroys all types of algae, will not cause staining and controls algae slime in swimming pools. This product's concentrated formula is non-staining and leaves absolutely no residue. Whether you want to kill existing algae blooms or simply prevent future algae growth, Pool Mate Algaecide 50 is an excellent value. Swim right after treatment. For use in gunite and vinyl pools. Dosage: Use 1.4 oz. for every 10,000 gallons pool water for maintenance each week. This product is compatible with most chemicals used in pool water and will not damage tile, concrete, metal or plastics. For us in swimming pools and outdoor spas: Add this product directly to the pool water along edges while filter and pump are in operation. To provide time for even distribution in the pool water, bathers must wait a minimum of 15 minutes after the addition of this product before entering the pool. For initial treatment of clean pools and spas, add 5 to 8 fluid ounces of this product for every 10,000 gallons of water (2 to 3 ppm active quaternary). Maintenance additions of 2 to 3 fluid ounces per 10,000 gallons (0.5 to 1 ppm active quaternary) should be added every 7 days, or more frequently depending on water and use factors. A booster dose of 2 fluid ounces per 10,000 gallons (0.5 ppm active quaternary) should be provided after each rain. For pools and spas with visible algae, add 14 fluid ounces of this product for every 10,000 gallons of water (5 ppm active quaternary). After 24 hours, remove dead algae by cleaning. If algae is still present, repeat dosage as necessary.