Phosphates are a prime contributor to the overgrowth of algae in aquariums. Use of specialized phosphate control filter media, such as these, can help reduce algae woes.
Chemi-pure Elite is a phosphate removing media sold in pre-filled nylon bags that are ready for use in your filter. Formulated for use in both freshwater and saltwater aquariums, it will not affect pH. Two formulas are available, Chemi-pure, which is a standard all-purpose filtration media, that also contains ammonia binding properties. The other formula is Chemi-pure Elite, which adds ferric oxide to the mix to remove both phosphates and silicates. Each 6.5 ounce bag of Chemi-Pure Elite treats up to 20 gallons; while the 11.74 ounce bag treats up to 40 gallons. The extra large 46.96 ounce bag treats 175-200 gallons. Remains active for 4 to 6 months.
Produced by Hagen as part of the Fluval line of media, Clearmax Phos-X is a filter media that contains phosphate removing resins in addition to standard filter media. Comes packaged with 3 pre-filled bags in one box. Each treats up to 100 L of aquarium water, and can be used in either freshwater or saltwater aquariums.
Designed for use with Rena Filstar filters, these phosphate absorbing pads are a reasonably priced product that removes both phosphates and silicates. Owners have reported using them successfully in other filters of similar size and shape. Suitable for either freshwater or saltwater, one pouch will treat up to 55 gallons of aquarium water. They come packaged singly, or three pouches to a package.
Kent Phosphate Sponge comes in the form of a ceramic filter media that can be placed in bags or media compartments in any filter. It will work in either freshwater and saltwater aquariums, and does not release soluble aluminum compounds into the water. I've used this media regularly with good results in a short time frame. Sold in a one quart size that will treat up to 120 gallons of aquarium water.
The Marc Weiss Phosphate and Silicate Magnet is offered as a granular filter media that can be placed in filter bags or compartments. The eight ounce jar will treat up to 125 gallons of aquarium water, removing phosphate and silicates for as long as six months. Suitable for both freshwater and saltwater aquariums. I've found this to be a good product, but it generally is higher priced than comparable products.
PhosGuard is a Seachem filter media that will remove inorganic and organic phosphate. It can be used loose in filter compartments, or placed in filter bags. Available in a range of sizes, including 100 ml 250 ml, 500 ml, 1 L, 2 L, 4 L, 20 L, and 100 L. Each 500 ml of PhosGuard™ treats over 150 gallons of aquarium water. What I particularly like about Seachems product is that they make a point of stating that it cannot be recharged. Much like carbon filter media, aluminum oxide products cannot be recharged, even though many sources on the Internet state they can be. Kudos to Seachem for telling it like it is.
Several manufacturers offer general purpose phosphate-removing filter pads. The pads are all similar in composition, and can be cut to fit the size and shape of the filter. They also serve a secondary role of mechanical filtration, making them a good option for virtually any filter that has space for a pad.
PO4X4 Phosphate Remover is a mini pellet media that is reportedly formulated with pure FeOH2 to provide better phosphate binding capabilities. The small size of this media does increase the surface area, and therefore should increase the phosphate removal properties. Although designed for fluidized bed filter systems, they can be used in canister filters as well.
Originating in Germany, this product was formulated to treat water in public supply mains to remove phosphate, arsenic, and silicate. It will bind phosphate without releasing it back into aquarium water in either freshwater or saltwater aquariums. Offered in 100 ml, 250 ml and 500 ml sizes. 100 ml will treat up to 200 gallons of fresh water.
SeaGel™ is a Seachem product that combines carbon filter media with a phosphate remover. It removes organics, phosphate, silicates, toxic metals, and acids. It is an effective product, but the cost makes it impractical to use as the only filtration media in your filter. Although formulated primarily for saltwater aquariums, it can be used in freshwater aquariums that have not been phosphate buffered. It can be used in a fine mesh filter bag in any filter that accepts bags. 500 ml will treat up to 120 gallons of aquarium water. Available in 100 ml, 250 ml, 500 ml, 1 L, 2 L, 4 L, and 20 L.
Two Little Fishies NPX Bioplastics are a small pelleted media that removes phosphate by promoting the growth of nitryfying bacteria. Designed for fluidized bed filters, it can be bagged and used in other filtration systems. A high flow rate through the filter is recommended for optimal performance. It is also recommended to be combined with Two Little Fishies PhosBan to provide peak phosphate removal. Available in 200 ml, 400 ml, and 1 L sizes.