HTH, 18 LB, Mineral Brilliance Chlorinating Granules, Calcium Hypochlorite 56.4%, Concentrated Granular Chlorinator, Fast Dissolving, Maintains Brilliantly Clear Water, Good For All Pool Surfaces. BENEFITS: Sanitize, clarify, and soften the water in your swimming pool so it is always ready for fun USE: Apply directly to pool water, broadcasting it evenly over a wide area in the deepest part of the pool; Add granules while filter pump is running during the evening; Use clean, dry scoop only used for this product COMPATIBILITY: Chlorine and saltwater systems FEATURES: Kills bacteria and algae; crystal clear results in 24 hours; prevents scale formation; turns blue to show it��s working; softens water; provides filter aid; fast dissolving INCLUDES: One 18-lb container of Ultimate Mineral Brilliance Chlorinating Granules for swimming pools