BENEFITS: Increases the chlorine level in swimming pools to kill bacteria and algae to keep your pool water clear and ready for fun all season long USE: Apply directly to pool water as needed; Test pool water and shock weekly to keep free available chlorine levels between 1 and 4ppm COMPATIBILITY: Effective for all swimming pool types including pools with liners and Gunite pools, and saltwater pool systems FEATURES: Increases chlorine levels; Kills and prevents bacteria and algae; Keeps water clear; See results in 24 hours; 1 bag treats 13, 500 gallons; Won’t fade vinyl pool liners INCLUDES: Twelve 1-lb bags of shock treatment for your swimming pool