EasyCare 50064 FounTec Algaecide and Clarifier, 64 oz. Bottle Fast acting and no chlorine needed Kills and inhibits all types of algae growth in all types of waters Treats over 2400 U.S. Gallons with recommended dosage: one drop per gallon of water per week Keeps Water Crystal Clear and Algae-Free Kills & Prevents Algae Growths