GLB one-half ounce tablets provide 90% available stabilized chlorine. These tablets can be used in floaters, feeders and skimmers. Dosage 1 tablet per 450 to 900 gallons every week or as often as needed to maintain a chlorine residual at 1.0 to 4.0 ppm Manufacturer GLB Manufacturer Part # 71250A Pool Chemical Type Chlorine and Bromine Product Features * 99% trichloro-s-triazinetrione * 1/2 ounce tablets * Easy to use and convenient