Ecosavr is an internationally acclaimed evaporation inhibitor that works as an alternative to conventional solar blankets. After 10 years plus a proven track record in commercial use, the non-toxic Ecosavr containing patented Heatsavr works! They're simple easy to use!How to use your Ecosavr liquid solar blanket:-Snip the top fin across the dotted line.-Squeeze the fish until the air has been evacuated & a small amount of the Liquid comes out.-Throw the fish in. It will sink to the bottom of the pool slowly releasing the Heatsavr liquid for about 25 days.Ecosavr wont effect your pools water chemistry or filter system & they're harmless to personal contact. Use 1 fish per about 10,000 gallons or up to 400 square feet of pool surface area per month. About 80% as effective as a solar blanket without the hassle!