6 in 1 Formula: Kills bacteria and algae to maintain a clear swimming pool. Our algae-fighting formula prevents algae for crystal-clear water. Destroys contaminants to aid filter performance and clear dull, cloudy water Swim-ready in 15 minutes: Fast dissolving formula works quickly so you can treat and swim in just 15 minutes. Compatibility: This product is safe for all swimming pool surfaces, including vinyl, plaster, fiberglass, and tile. Usage: Use 1 lb. per 12,000 gallon of water. Shock pool weekly and after heavy use, high temperatures, or rain. Clorox Pool App: Test like an expert anytime, anywhere with the Clorox Pool App. Solve common pool problems and get personalized product and dosage recommendations.