Blue Wave®'s premium pool chemical stabilized chlorine features U.V. protection to shield it from the sun, and is manufactured using only the highest quality, EPA-approved chlorine. Blue Wave® oversees a strict quality-controlled tabletting process, which guarantees the optimum hardness of each tablet. This keeps pool chemical tablets from dissolving too rapidly and ensures proper chlorine dosages 24 hours a day. You will find that Blue Wave® chlorine dissolves completely with no residue.