Cleans Water & Stops Algae: Kills harmful bacteria and prevents equipment corrosion, scale and stains. Kills and prevents all types of swimming pool algae (green, mustard, black) Long-lasting sunlight protection: Contains chlorine stabilizer to extend the life of your clean Creates Silky Smooth Feeling Water: XTRABLUE chlorinating tablets contain conditioners for silky smooth feeling water Usage: Apply 2 tablets weekly to treat 10,000 gallons of water, add more tablets as needed to maintain adequate sanitation. Safe for all swimming pool surfaces, including vinyl, plaster, fiberglass, and tile. Clorox Pool App: Test like an expert anytime, anywhere with the Clorox Pool App. Solve common swimming pool problems and get personalized product and dosage recommendations