Premium grade, fast-acting, fast-dissolving 73% calcium hypochlorite granules. Shock treatment and super chlorinator for pools. This granular calcium hypochlorite kills bacteria, controls algae, and destroys organic contaminants. Great for all pool surfaces. Features: - Puts the sparkle back in dull, flat water - Helps eliminate unpleasant odors & conditions that cause eye irritation - Increases chlorine efficiency - Kills bacteria, controls algae, and destroys organic contaminants