HTH Super Shock-N-Swim Pool Shock - 32 x 1 Pound Bags 32 x 1 pound bags Use weekly to kill bacteria, control algae, soften, clarify and polish dull water Contains calcium hypochlorite with 53% available chlorine Fast dissolving HTH shock is buffered to reduce pH fluctuations during use Dosage: 1 lb. per 12,000 gallons