The 73 Pool Shock is 73% Calcium Hypochlorite with 70% available chlorine. This granular formula comes in a bucket and saves you time and money by quickly dissolving to destroy waste, algae, and bacteria in your swimming pool. This powerful shock treatment is great for spring start up, gives a quick chlorine boost, and helps to balance your pool water chemistry. One pound treats 16,500 gallons of pool water. Use the 73 Shock Treatment in your swimming pool for more fresh and clear pool water. 50lbs buckets. Pool Shock and Super Chlorinator 70% available chlorine, Pool Shock and Super Chlorinator Fast dissolving granular formula 1 lb will provide 2ppm of available chlorine in 40,000 gallon pool Kills 99.9% of bacteria or algae Kills 99.9% of bacteria or algae|Fast dissolving granular formula|1 lb will provide 2ppm of available chlorine in 40,000 gallon pool