SeaChem Purigen is a premium synthetic adsorbent that is unlike any other product! It is not a mixture of ion exchangers or adsorbents, but a unique macro-porous synthetic polymer that removes soluble and insoluble impurities from water at a rate and capacity that exceeds all others, even HyperSorb, by over 500%. Purigen removes proteins, nitrites and nitrates, ammonia, and a broad spectrum of organics, yet its impact on trace elements is minimal. It significantly raises redox. It polishes water to unparalleled clarity. Like HyperSorb, Purigen darkens progressively as it exhausts, and is easily renewed by treating with household bleach. A 250 mL bag of Purigen purifies and polishes up to 250 gallons of water for up to six months. Purigen is designed for both marine and freshwater use.