What Is A "Biological Filter"?

The biological filter in a saltwater aquarium is nothing more than a place for bacteria to grow. Any surface in an aquarium which comes in contact with tank water and the nitrobacter & nitrosomona bacteria species that you created when you cycled the tank is part of your bilogical filter. The velocity of the water passing over the bacteria also affects the efficiency of the biological. The faster the water moves over the bacteria, the more efficient it is, up to the point where the bacteria is being stripped from the filter surface.

The efficiency (strength) of a biological filter is determined by its surface area and the amount of water passing over it. Some filter medium are more efficient than others. Aquarium glass surface area aside, here are the most popular biological filtration methods:

• Canister Style Filters come in many different styles and sizes and can also be multifunctional.
• Live Rock / Berlin Systems are the filters of choice for many SW aquarium purists.
• Live Sand / Jaubert Systems are also very popular with many reef aquarists.
• Undergravel Filters are among the first biological filters created for SW aquarium hobbyists.
• Wet / Dry Trickle Filters were the next step after the UGF to dramatically improve efficiency.
• Biological Filtration Polls show you which biological filters are popular with other habbyists.
• Choosing Your Biological Filter Material shows you which materials are more efficient.

Knowing how each biological filter works and what it requires will make Choosing a Filtration System In 5 Easy Steps much easier.