Clorox Pool&Spa Algaecide + Clarifier prevents and treats pool algae. Being one step ahead of algae is crucial because as algae grows chlorine must work harder to keep your pool clean. But don t worry. You have solutions that will keep your water blue and clear from those uninvited green guests (that have no problem overstaying their welcome in your beautiful pool.) Consider using a preventative pool algaecide weekly if your pool is prone to algae or when the temperature increases during the peak of summer. Always apply chemicals according to label directions. Circulating pool water when applying chemicals helps disperse chemicals throughout the pool for maximum coverage.