SeaKlear Solar Shield 1 Gal Unique, patented formulation provides best-in-class evaporation protection (US patent #: 8021545) Long-lasting formula can be dosed monthly or weekly in high evaporation conditions Reduces evaporation in the first week of use Can help prevent the loss of up to 1,5000 gallons of water per month (In 15,000 Gallon Pool) Perfect for large and irregularly-shaped pools