Canister filters are external filters which allow more flexibility and more amounts of filter materials compared to power filters. More filter material choice makes these filters very useful.
An intake pipe at the bottom of the canister allows water to enter a canister of filter material. This water is then passed through material and a return pipe feeds it back to the aquarium. The top of canister has a pump installed which forces water to circulate through the filter. The return pipe and the intake pipe along with filter interior and aquarium form a continuous body of water and make canister filters sealed, fully flooded systems.
The intake and return path form two siphons in such a pattern to balance one another. This is why even if the aquarium is installed high above canister there is no extra effort required to lift the water back to the aquarium. Canister filter pumps are nearly insensitive to the height difference between filter and aquarium and the pump only needs to have enough power to push the water through the filtering material and overcome the intake and return pipe drag. Leaks can happen as a result of exceeding manufacturer-specified height limit.
Canister filters never decrease the aquarium's internal space and that is one of the major benefits. Other than that, Canister filters provide a high volume of filter material. For cleaning and maintenance tasks, Canister filters can be easily disconnected without causing disturbance to the fish or the aquarium interior and replacement is just as easy.
Canister filters come with external plumbing and in-line installation of other aquarium equipment is supported. This means you can add or remove equipment like carbon dioxide diffusers and water heaters.
Some disadvantages include risk of a leak especially when filter is placed outside of the aquarium and the higher cost. You will also have to face some complexity relative to internal filters cleaning the tubes which transfer water to and from the aquarium isn't as easy.
The initial function of Canister filters was to filter drinking water. ut that took place under low pressure conditions. Now, Canister filters use high water pressure for aquarium filtering and for double filtration for use with under-gravel filter. A suitably powered pump is used to force water through the dense filter media.
Canister Filter Manufacturers
- Aquarium Pharmaceuticals
- Marineland Magnum