These Leisure Time 12 Piece 2 lbs. Spa Chlorine Granules are designed to dissolve quickly and completely. The chlorine granules provide a steady source of available chlorine to spa water to control algae growth, kill bacteria, and destroy organic contaminants. Granules are stabilized to protect against ultraviolet radiation from the sun, which increases the life of your chlorine. It's available in two-pound bottles.