Swamp Treat is a proven method, which will clean even the most challenging and detrimental of algae within 24 hours or less. Swamp Treat works by improving and speeding up your chlorine’s algae fighting ability using your pool filtering system, and just a single 1 lb. bottle will restore 20,000 gallons of water to impeccable condition. Swamp Treat is non-toxic, and the formulation doesn’t include metals, so you don’t have the concern of stains or altered water balance when you use this product. Product Type: Rescue Algaecide Used For: Heavy infestations of all types of algae Dosage: 1lb. per 20,000 gallons In addition, you need to add 2lbs of shock immediately after to “activate” the product.