Pooltec 3-in-1 Pool Water Treatment, Algaecider,Water Clarifier and Chlorine Booster. Continuous prevention of green, yellow and black algae. Kills most algae in 4 to 24 hours. Strong clarifiers create ultra-clear water.· Boosts chlorine’s effectiveness up to 6X (600%).Improves salt cell’s chlorine output and performance. Powerful treatment for heavy use and salt cell pools. Very effective even at phosphate levels above 5,000 ppb.