Hasa 77141 1 gal Bottle Phos Out 4 per case. Phos Out is proven to eliminate phosphates from sources such as fertilizers, detergents, pool chemicals, and other pollutants. Phos Out is not-toxic and 100% safe for your family and the environment. Phos Out is effective and just one quart removes up to 1,000 parts per billion of orthophosphates per 20,000 gallons of water. Use 1 ounce per 5,000 gallons of pool water to maintain phosphate levels below 125 ppb as part of your weekly maintenance routine.