HyperSorb is a synthetic adsorbent that outperforms all other blended synthetic media and carbons. It has exceptional organic removal capacity: it removes organic waste, toxic vapors and other pollutants. In freshwater it will help stabilize the ionic balance and will help control ammonia, nitrite, and nitrate. It is easily regenerated with household bleach. Marine and freshwater. This product is sold by volume. Cited weight is minimal weight.