Protect your indoor and outdoor swimming pool against bacteria, algae and other organisms and enjoy clean, clear water with hth® 3 in Chlorinating Tablets. This stabilized chlorine sanitizer comes in 3 in tablets for use in feeders, floaters and skimmers they're also compatible with saltwater systems. Convenient and easy-to-use, one tablet treats 10,000 gal of water for up to one week. Best of all, these chlorine tablets contain cyanuric acid to help protect against chlorine loss due to sunlight. Spend more time splashing and less time sanitizing with hth® 3 in Chlorinating Tablets for Swimming Pools. To Use : Place one tablet in pool feeder, floater or skimmer per 10,000 gallons of water every week or as often as needed to maintain a chlorine residual of 1 to 4 ppm. Do not add directly to the pool as this can cause damage to pool surfaces.