Cal-Hypo Super Strength Pro Pool Shock 50 LB Bucket is a calcium based chlorinated granular shock. It is 73% Cal-Hypo and 70% Available Chlorine. That makes this the strongest granular shock you can buy. It quickly dissolve, Maintaining proper chlorine is essential to keep your pool safe for swimming. Cal-Hypo can be used as a maintenance product or treatment product. Pools that are prone to debris, sunlight, and swimmers may require more frequent doses. Usage Directions:Routine ChlorinationAdd 16 ounces of Cal-Hypo per 16,500 gallons of water directly to the pool, casting it around the perimeter as often as needed to maintain the desired free chlorine residual. Common Questions:What makes this the most powerful shock?The product is 70% available chlorine, which is the highest concentration of chlorine in a granular product you can get. Can my water get cloudy after adding?Yes, This is a calcium based chlorinated shock. While quick dissolving the calcium still takes time to be accepted into solution. How should I add this to my pool?Broadcasting it across the surface or walking around the perimeter evenly distributing the granular around the pool.