SOLARPILL minimizes heat loss by forming a harmless ultra-thin, invisible barrier on the surface of the water to reduce evaporation. Its patented delivery system gradually releases the formula into the filtration system to allow for optimum coverage. One capsule treats a 30,000 gallon (45,000 liter) pool for one month. Replace when necessary to maintain water temperature. SOLARPILL can be used with ALL types of sanitizers, is safe for all pool chemistry.