Poolife Rapid Shock dissolves fast to bring your chlorine levels back into balance. Rid your pool of contaminants from heavy pool usage, rain or windstorms with this weekly shock. Product Dosage 10-20 ounces per 10,000 gallons of water to provide 5 to 10 ppm available chlorine every week. Directions Do not pre-mix this product. Only add this product directly to your pool or skimmer. Use only a clean, dry scoop to measure this product. Do not use the scoop for any other purpose. Method of Application: Add the recommended dosage of this product during evening hours while the filter pump is running. When adding this product your pool, broadcast the product evenly over a wide area in the deepest part of the pool. If any granules settle to the bottom of the pool use brush to disperse. Method for skimmer addition: Make sure that filter pump is on and properly recirculating through skimmer. Empty skimmer of all chemicals and/or debris. Contamination may cause an explosion or the release of toxic gases. Do Not use this method when an automatic chemical dispensing device (e.g. Feeder) is present. Pour this product slowly into skimmer, making sure that the material is drawn into the system at the same rate, do not allow this material to accumlate as toxic gases may be generated. Water Balance: For best product performance, swimmer comfort, and crystal clear water; Maintain pH in range of 7.2 to 7.6. Maintain total alkalinity in the range of 60 to 120 ppm. Maintian calcium hardness above 200 ppm. Use a reliable test kit that measures these ranges. Do not enter pool unitl the free available chlorine residual is 1-4 ppm.