Rx Clear Multi-Purpose Tabs (40 Lbs) Rx Clear 3" Multi-Purpose Tablets, contain a blend of ingredients that will reduce the amount of chemicals required to maintain your pool water. These 3" individually wrapped stabilized tablets contain a blend of stain inhibitor, algae control, descaler and water clarifier to keep your pool water crystal-clear. Tablets can be used in automatic feeders and floating chlorinators. Available Chlorine 84.65%