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How Do Canister Filters Work

how do canister filters work

The filtration system is an integral part of the maintenance and cleaning of the aquarium. But, there are various types of filtration that you can use in the fish tank. One of the more popular is the canister filter because of its low maintenance and silent operation.

But how do canister filters work? A canister filter comes with an external chamber or simply called a canister, containing different filter media types. The aquarium water will be pushed into the canister to get filtered before returning to the tank using an outlet.


Step-By-Step Guide on How Canister Filter Works

The canister filter works in the principle of siphoning the aquarium water using either a valve, a strainer, or an intake tube. The water will then be pushed into a pressurized canister containing filter media and pumped the aquarium water back into the fish tank.

Step 1: Drawing the Aquarium Water

The initial step is drawing the aquarium water outside the aquarium using a lift tub. The destination of the aquarium water is actually a pressurized canister that contains a series of filtration media that cleans the aquarium water inside the canister.

Please note that the direction of the aquarium water flow varies depending on the brand or model of the canister filter. The direction of the flow can be from outside to inside, top-to-bottom, bottom-to-front, back-to-front, and many more.

Step 2: The Actual Filtration Process

Once the aquarium water goes inside the canister, the water will then be pushed via a pump to the part of the canister where the filtration happens as the water passes through a series of filtration media.

This filtration media will provide the filtration of the aquarium water. It offers different types of filtration, such as biological, chemical, or mechanical filtration, depending on the filter media being used with the canister filter.

Step 3: Returning the Water to the Aquarium

Once the aquarium water is filtered inside the canister, it will be pushed back to the aquarium using a pump. The canister filter will also use a water pump to move the aquarium water because the canister’s filtration system is permanently sealed.

They are canister filter models that come with an integral water pump in the product. These water pumps are built-in and are usually located on the cover or the base. There are also other models that require a separate external water pump.

The Upside of a Canister Filters

the upside of a canister filters

There are many reasons to use a canister filter in your aquarium. Most canister filters are used by aquarium owners who own large fish tanks. So, what are the advantages of using a canister filter in the aquarium? Please see the list below:

Ability to Hold Several Filter Media

This feature is the primary reason to use a canister filter. Its ability to hold several filter media in different forms such as biological media, chemical media, or even mechanical media. This media can be involved in chemical filtration, such as filter sponges, filter flows, and other usages.

Ability to Give a Good Water Flow

Regardless of the size of the fish tank, using a canister filter will provide a good water flow in the fish tank. Unlike other filtration systems, you can put the return and intake on the separate sides of the aquarium, which results in excellent water flow.

Other filtration systems come with the return, and the intake comes close together, affecting the water flow. With the canister filter, they can be separated, which means it will provide an excellent mechanical filtration system in the aquarium.

Canister Filters are Generally Quiet

Canister filters work in silence. You will not hear any noise or sounds during its operation compared to other types of filtration. So, if you have a centerpiece fish tank in the living room or any other special place in your house and do not want to hear the filter running, a canister filter is an excellent choice for you.

Filter Not Visible

Another upside to using a canister filter is you do not see a lot of filtration in and around the fish tank. The canister filter can be easily hidden under the tank. The only thing you are going to see in the tank is the intake and the return, and that’s about it.

The Downside of Canister Filters

There are also some disadvantages of using a canister filter. Please see the list below:

Not Economical

If you own multiple tanks, it does not make sense economically to use a mechanical filter in all of them. Canister filters are one of the most expensive fish filters you can use in your fish tank, which is a disadvantage if you have a limited budget allocated for your fish tank.

Difficult to Maintain

Canister filters are difficult to maintain. When cleaning, there are so many things to do that will require you to use a lot of time when removing the filtration setup. Personally, it is quite annoying because other filtration systems can be maintained easily.


Learning how do canister filters work is essential for you to know the pros and cons of this filtration system. It will also help you decide in the future if you will use this type of filtration system or try something else.

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