| As a beginner aquarium keeper, one of the first | | | | Canister filter |
| types of mechanical filter that you encounter is | | | | For aquarium keepers that keep messy eaters or |
| probably the trusty old corner filter. The corner | | | | have large aquariums, the basic corner filter is |
| filter is inexpensive to purchase compared to | | | | often not enough to keep the water quality up. If |
| many other types of mechanical filters, and also | | | | you find your self in this situation, you might want |
| easy to install. The basic corner filter will be a | | | | to consider the canister filter. This filter is an |
| plastic container filled with a filter medium, e.g. | | | | external filter that is hung outside the aquarium or |
| foam or floss. An air pump will be used to force | | | | placed under the aquarium. Today you can also |
| water through the filter, thus trapping larger | | | | find canister filters that are located inside |
| debris. A corner filter will therefore often also | | | | aquariums (submersible canister filters), but they |
| function as an aerator for the aquarium. | | | | are much less common than external canister |
| Be careful when you clean your filter medium and | | | | filters. The inside of this filter will typically contain a |
| never use hot water or detergents. When you | | | | micron filter cartridge, glass wool or similar types |
| have performed a water change, the discarded | | | | of filter media. Waster is then pumped through |
| water can be used to wash the filter medium | | | | the canister filter, and larger debris is caught in the |
| since it will have the right temperature, pH etc. | | | | media. This makes the canister filter quite similar |
| The reason why you should handle your filter | | | | to the basic corner filter, only much larger and |
| media so carefully is that it is a great home for | | | | more powerful. You can also add a wet-dry wheel |
| beneficial bacteria. If colonies of nitrifying bacteria | | | | to your filter to promote biological filtration. |
| colonies the filter media, they will perform | | | | Just like with the corner filter, you must clean |
| biological filtration and make it much easier for | | | | your canister filter frequently to prevent clogging. |
| you to keep the water quality up in your | | | | If the caught debris is left too long in this filter, |
| aquarium. Hot water, detergents etc will however | | | | they will start decomposing and can pollute the |
| kill the bacteria and must therefore be avoided. If | | | | water. A negative aspect of the canister filter is |
| you need to replace the filter media, you should | | | | of course that it requires a lot of space. A |
| ideally leave a part of the old media in the | | | | submersible canister filter will take up a lot of |
| canister filter. This way, the old bacteria can | | | | space and look ugly inside the aquarium, while an |
| colonies the new filter media. | | | | external canister filter will take up a lot of space |
| A downside with the corner filter is that many | | | | and look ugly somewhere outside the aquarium. |
| designs produce a lot of noise. You can of course | | | | Careful planning can be the solution here; you can |
| find good looking corner filters, but a majority of | | | | for instance hide the external canister filter in a |
| the corner filters are actually quite ugly. If you | | | | piece of aquarium furniture. Just keep in mind that |
| have messy eaters, the corner filter will be rapidly | | | | it must be easy to access the canister filter, since |
| clogged and require frequent cleaning. The corner | | | | it requires frequent cleaning. Never use soap or |
| filter can also be insufficient for aquariums that | | | | hot water when cleaning your filter. |
| require more vigorous filtration. | | | | |