SUN 1lb Bag SunBurn Extra Cal Hypo Shocks, oxidizes and clarifies in one step. Now theres a pre-measured, granular calcium hypochlorite formula that uses multi-functional technology to destroy organic contaminants and keep water clean in one easy step! SUN-Burn Extra dissolves quickly and is conveniently packaged in 1 lb. bags for exact dosage and optimum freshness. One bag treats 20,000 gallons of water every week. Ideal for vinyl and plaster pools.