Slowly lower the pH of pond water (making it more acidic) without harming delicate pond fish or aquatic plants. Slowly neutralizes alkaline substances that cause high pH (pH of pond water is affected by mineral leaching, soil runoff & decomposing waste). A high pH limits the ability of aquatic plants to absorb necessary nutrients. Contains no algae-promoting phosphates. Directions For Use: 1. Test the pH of the pond water with a PondCare Liquid Wide Range pH Test Kit. 2. Add 1 teaspoonful (5 ml/ 5 cc) of pH Down for every 50 U.S. gallons (189 L) of pond water. 3. Wait 24 hours, then test pH. Repeat treatment as necessary.