Saltwater Filtration

Mechanical: physical removal of debris & particles from water with the use of foams, pads, filter floss or filter cartridges.
Chemical: absorption of pollutants by using types of carbon or a Poly filter®.
Biological: encourages growth of beneficial bacteria and breaking down toxic ammonia and nitrites into Nitrates (Nitrogen cycle).
Power filter: an external filter, pulls water out of aquarium, through the filter media and back into the aquarium. Usually biological, mechanical and chemical.
Canister filter: an external filter, pulls water out of the aquarium, through the filter media and back into the aquarium. Biological, mechanical & chemical.
Under Gravel filter: internal filtering system, a plate that goes under the gravel with lift tubes that are operated by a powerhead or an air pump and airstones.
Wet/dry filter: an external filter, pulls water out of the aquarium, drips through filter media. Clean water is pumped back into the aquarium. Uses biological, mechanical and chemical system.