Clorox Pool&Spa XtraBlue 3" Long Lasting Chlorinating Tablets 25 lbClorox pool amp, spa xtrablue 3" long lasting tablets protect against algae & bacteria for water that stays clean, clear & amp, free of visible algae.Clorox Pool&Spa 43128CLX 42128CLX Pool Algaecide"Clorox® Pool&Spa™ Algaecide + Clarifier prevents and treats pool algae and includes a built in clarifier to keep water clear. Being one step ahead of algae is crucial because as algae grows, chlorine must work harder to keep your pool clean. Use as a preventative pool algaecide weekly to keep algae at bay and your water crystal clear. Always apply chemicals according to label directions. Circulating pool water when applying chemicals helps disperse chemicals throughout the pool for maximum coverage."