3" Trichlor chlorinating tablets are self stabilized with a built in stabilizer containing cyanuric acid, which helps prevent sunlight from degrading the chlorine. 90% available chlorine is released when the product is dissolved in water and works continually to kill bacteria, control algae, and destroy the organic contaminants in water. Upon contact with chlorine, bacteria and other contaminants are oxidized. Simplifies pool care with long lasting routine chlorination via convenient skimmer, feeder, or floater application. Gentle on pool equipment and surfaces. Ideal for all pool surfaces. Clears up hazy water and helps prevent future algae growth.