There are many forms of biological filter materials (balls, ceramic rings, foam, pellets, 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" 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 are durable fairly easy to use and should never have to be replaced.
By Lifegard, the BioMate Filter Media Balls take bio balls one step farther. These refillable plastic balls come in 1" and 1 1/2" sizes. Choose from Solid, Carbon-Filled, Foam-Filled, or Ceramic-Filled. Mix and match the materials to get the affect to want from your wet/dry trickle, canister or corner box aquarium filtration system.
The Quartz Ball Biological Media by Azoo's spherical shape resists clogging and compaction for optimal water flow. The Quartz Ball has an enormous porous surface area for intensive bacterial colonization. Made from natural lava rock processed under high temperatures, this media can be used in the biological filtration system of both fresh and saltwater aquariums.
Bio-Glass by Azoo is made from natural silicate fused at a high temperature. Its pore structure gives it up to 8 times more surface area, compared to other bio-rings. It can be used in a wide variety of filtration systems like submersible, canister, wet-dry, and power filters. For fresh or saltwater aquariums.
Bio-Chem Stars by Rena FilStar 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. For use in either fresh or saltwater aquariums.
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 while pores are perfectly sized for bacteria colonies. Each ceramic cylinder measures approximately 5/8" dia x 3/4" long. The 17.63 oz box contains approximately 100 ceramic cylinders.
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 essential for the break down of toxic ammonia and nitrate. Shaped like egg crate foam, the Bio-Foam effectively traps smaller particles and debris for greater mechanical filtration.
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 the bacteria population. See Using Activated Carbon in Saltwater Aquarium Systems for more information (including the pros and cons) about using carbon in your system.