Naturally occurring organisms will decompose the lignins in the barley releasing humic substances into the water. With exposure to sunlight and oxygen the compounds are converted into low levels of hydrogen peroxide, modifying your pond's chemistry and improving water quality. Each 1lb bale treats approximately 100 square feet of pond surface. Lasts approximately three months. Install replacement bale three weeks prior to removing old bale for continued coverage. Safe for use with aquatic life and pets. Includes mesh bag for easy application. Best results if applied early season. 1 bale per 1000 gallons of water.