The API Nitra Zorb is a filtration media that is scientifically proven to remove aquarium toxins. Nitra Zorb is a ready-to-use filter media pouch that can be added to your filter to remove ammonia, nitrite, and nitrate. Nitra Zorb is made of natural and synthetic ion-exchange resins that selectively remove toxins from freshwater aquariums. Nitra Zorb is completely phosphate-free and can be reused after recharging. Removes ammonia, nitrite, and nitrate. API Nitra Zorb Comes in a ready to use filter media pouch. Made of natural and synthetic ion-exchange resins that selectively remove toxins from freshwater aquariums. Directions: Rinse pouch under tap water. Place pouch in path of water flow in the aquarium filter. For a new aquarium or when ammonia or nitrite is detected: recharge every 5 days for the first month, and then every 2 weeks for the second month. For an established aquarium: recharge every 2 weeks. When nitrate is detected: recharge every 5 days until nitrate is reduced to 20ppm (mg/L) or less. Replace pouch after 2 months. To recharge: Dissolve 80g of API Aquarium Salt in 240 ml of warm tap water. Soak pouch for 2 hours, then rinse lightly in tap water. When not in use, store pouch in recharging solution. Size: 210g (treats up to 208L) Suits: Freshwater Aquariums Only