I've never used zeolite myself but I did want to mention that carbon can not be recharged. Purigen can be recharged as well as some resins. However they are typically difficult processes invloving bleaching and acids. Carbon only has a useful life of about 4 days. After that it drastically reduces it's working capacity. Powder carbon is the best as it has the most surface area. But that is also it's downside as it only lasts about 24 hours. It just works that well. Spherical is the second best as water flows in a consistent pattern around the surface of the balls. It lasts about 4 days. Rod carbon lasts longer. That however might not be a good thing. The manufacturers can claim a useful life of 2 weeks with rod. It only means it works that much SLOWER. The irregular shape prohibits good water movement and prevents the useful areas of the carbon from ever working. So with rod shaped carbon keep in mind that when you through it away, it might not have used it's full potential but only because of the poor design. IMO balls or spheres are the most appropriate shape for aquarium use. Powder is great for emergencies but then again so are water changes.
forum community dedicated to tropical fish owners and enthusiasts. Come join the discussion about species,breeding, health, behavior, aquariums, adopting, care, classifieds, and more! Open to fish, plants and reptiles living in freshwater or saltwater environments.