An Aquarium External Filter is an excellent form of fish filter. From the range of Eheim professional to fluval external filters they are an ideal method of maximising filter surface area to ensure most efficient aquarium filtration. An aquarium canister filter or external filter is typically placed alongside but more often underneath the aquarium in a cabinet.
The external aquarium filter usually has two pipes, a feed and a return. The water passes from the aquarium into the aquarium filter and in turn is passes through a number of filter baskets. These filter baskets can contain a range of aquarium filter media including course and fine foams and sponges to purify the water both via chemical filtration and biological filtration. After this filtration process the water is then pumped back into the aquarium. The external filter can be used in tandem with an aquatic sump.
External filtration is certainly efficient and often seen as been more effective than other forms of aquarium filtration, for example an internal filter or undergravel filtration. The quantity and variety of filter media is much greater and by design more efficient as a result of the larger surface area. This enables the enthusiast to keep aquatic life in a more stable environment as a result of the beneficial bacteria.