Combines ammonia with ultra-grade carbon purification. Includes 3 pack of zeo-carb. Removes and prevents build-up of toxic ammonia. Eliminates odors, discolorations, and impurities. Available in various sizes. You may not want to actually eat off it, but your tank will be that clean when you use the Fluval Zeo-Carb - 3 pk. This one-two punch of clean combines ammonia with ultra-grade carbon purification to remove and prevent build-up of toxic ammonia. It eliminates odors, discolorations, and impurities. About FluvalA world leader in quality aquatic products and design, Fluval is trusted by fish-hobbyists everywhere for creating innovative products with stellar dependability. For over 30 years, Fluval has earned a global reputation based on their creative and innovative products. With an emphasis on convenience, ease of use, and durability, Fluval has lead the way in providing efficient and reliable canister filtration systems since 1982. Fluval's pioneering spirit and strong commitment to technological advance are exhibited in its wide range of products, from stylish and practical aquariums like the Fluval Edge, Profile, Chi, and Studio to their top notch Fluval G Series Filters. For the perfect intersection of design and technology, Fluval is the name to know. Size: C4 (between 40 - 70 gallons).