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There are many forms of biological filter materials (balls, ceramic rings, foam, pellets, plastic stars) used for aquariums. Some are more efficient than others, while some are easier to maintain. Here are some of the top biological filter media on the market today.
Bio Balls Biological Filter Media
"Bio Balls" are available in many sizes (1" to 2" in diameter) and designs (bio-pin, bio-ball). Offering an excellent surface area to volume ratio, bio balls are most frequently used in wet/dry trickle filters, they can also be used in almost any filtration area. Most filter material of the bio ball design is durable, fairly easy to use, and should never have to be replaced. Rinse in a container with some tank water occasionally to remove debris that gets trapped on them, then place them back into the filter. This gentle cleaning to remove debris will not wash off the beneficial bacteria that adhere to the bio ball surface.
Ehfisubstrat Pro by Eheim has an improved spherical shape which prevents clogging or compacting in your filter! It is still made of sintered glass for long-term use. Simply rinse well with aquarium water periodically to remove debris and reuse. Enormous surface area; ideal for the colonization of nitrifying bacteria.
Filstar Bio-Chem Stars
Bio-Chem Stars by API is a biological filter media for aquarium canister filters. Made of porous polymer material, Filstar Bio-Chem Stars provide a substrate for the optimum growth of beneficial bacteria, including nitrifying bacteria that convert toxic ammonia and nitrite into nitrate. For use in either fresh or saltwater aquariums. To clean the Stars, just rinse in tank water and return to the filter.
Fluval BIOMAX Filter Media
The Fluval BIOMAX Filter Media was designed specifically for Fluval Multi-Stage Canister Filters, however, they can be used in a wide variety of filter types. The porous ceramic cylindrical design allows a large population of bacteria to grow in a minimal space, and the pores are perfectly sized for bacteria colonies. Each ceramic cylinder measures approximately 5/8" diameter x 3/4" long. The 17.63 oz box contains approximately 100 ceramic cylinders. To clean the filter media, just rinse in tank water and return to the filter.
Fluval Bio-Foam was originally created for use in Fluval Canister filter models 04, 05 & 06, however, it can also be used in other applications. This "3-Dimensional" media features a pore structure that increases surface area for nitrifying bacterial colonization, which is essential for the breakdown of toxic ammonia and nitrate. Shaped like egg crate foam, the Bio-Foam effectively traps smaller particles and debris for greater mechanical filtration as well as the biological filtration. To clean the Bio-Foam, just remove it from the canister filter and rinse (squeeze tank water through it) and replace it in the filter.
Premium Pelleted Carbon
Activated carbon was originally designed for effective aquarium water purification. While not frequently advertised as such, due to its porosity and stability, pelleted activated carbon also makes an excellent biological filter media. Even when its adsorption capabilities are depleted, it can continue to provide an excellent platform for nitrifying bacteria. When the carbon becomes clogged, rinse in tank water to retain a majority of the bacteria population. Pelletized carbon will compact and become clogged over time, so agitating the carbon to break up the clog is a good idea. If some of the carbon is replaced monthly, it will also have the adsorption properties that carbon is typically used for, as well as acting as a substrate for the biofiltration bacteria.