In The Swim Pool Shock is our most economical chlorine shock treatment for pools, sold in convenient 1 lb. bags. Powerful formula contains 99% calcium hypochlorite in a powerful 68% available chlorine formula. Granular chlorine Pool Shock is used for a variety of purposes to sanitize and disinfect pools, spas and fountains. Easy to use Pool Shock effectively treats 10,000 gallons of pool water per bag. Use our Pool Shock to kill visible algae blooms and invisible bacteria, which could cause illness to swimmers. Your daily chlorination of the pool will kill most pathogenic bacteria, viruses and microbes, however to be sure that the water is sanitary, it is good practice to shock the pool, or super-chlorinate the pool every few weeks, to oxidize everything in the water, especially the invisible germs that may be harboring in the water. One pound of In The Swim Pool Shock will raise free chlorine levels in a clean and balanced pool to 9 ppm, per 10,000 gallons of pool water. Pools with excessive debris, algae, suspended particles or heavy sunlight will need a proportionally higher dose of pool shock, to compensate for such factors. A double or triple dose is often required for poor water conditions such as spring openings, bacteria contamination, or severe algae blooms.