What Exactly Is A Canister Filter And How Does It Work?

Canister filters have become one of the most popular choices for aquarium filters. Why is that so? Well, that is what we have written this article for and will be going over. They are one of the most reliable and efficient filters out there, which will leave little work and worry for you. To help you come to the conclusion on what a canister filter is, and how they work, let us break down all the information there is to know!

The primary job of every aquarium filter is to clean the water in the tank right? Yes! However, what separates the canister filter from the rest, vis a vis, how is it differentiated? There are 3 main parts to a canister filter; the cartridge, motor and tubing.

A canister filter operates basically with the help of a rotor and with gravity, to ensure that the water from the tank enters the mechanism, and comes out filtered through various chambers.

The cylindrical device containing the filter medium and pump is known as the main chamber. This area has two hoses which run from the cylinder into the aquarium. These are the intake and return pipes. What’s good about these is that they do not use any power because they utilize a siphon instead.

The size of your canister filter depends on the size of your aquarium tank, among various other factors. This isn’t the only factor that ensures a good canister filter, as you need to check many other factors when choosing the best canister filter for your aquarium.

Canister Filter Functionality

Since we have discussed the logistics of a canister filter and how useful they can be, let us now look into how they function.

Siphoning is the key function when it comes to canister filters’ functionalities. The intake and return pipes use the siphoning function to bring and exit water out of the canister filter. A siphon is created when there is a line of no interruptions in between two bodies of water. This allows for the water to move in between the filter and tank completely freely in the vertical positions.

As the siphon allows for the water to move through into the canister filter, the water then is forced through the three different filtration stages; mechanical filtration, biological filtration and chemical filtration.

After the filtration is completed, the water is then pushed back out of the canister filter back into the tank, as clean as it could be.

Canister Filters Compared Against Others

Canister filters are often compared to other filtration systems, and this creates for interesting conversations. The most common ones canister filters are compared against are HOB (hang on back) filters, among others.

We will primarily speak on the benefits of having a canister filter itself, and there are quite a few. One of the most basic and easy to notice one is that they take up no space in your tank. Since they are placed outside the tank, it saves space inside the tank. They also provide a great filtration area, which not only makes your aquarium healthier, but also creates problems such as clogs less likely.

While HOBs also provide more space in your tank by being placed outside, they are not as reliable or efficient when compared to canister filters. Also with the fact that they utilize the motor more than a canister filter, it makes HOB filters much more noisy and annoying for the both aquarium inhabitants and you. 

Are Canister Filters Worth Getting?

While canister filters are great, something to keep in mind is that canister filters require a bit of experience in order to optimally use them. However, if you can keep in mind the information provided to you in this article, it is definitely something to keep in mind.

Canister filters are overall the best choice when it comes to keeping your aquarium environment in the optimal condition for a long time. As the most common comparison goes against HOB filters, it should be known that they are much better at sustaining tanks with a higher number of inhabitants, whether that be fish or plants. 

Canister filters are even a great choice if you are looking to startup a turtle aquarium. Turtle tanks have very specific requirements, so the thoughts that go into making their tanks need to be very meticulous.

Cons of Canister Filters

Canister filters don’t really show many problems when they are being used, and primarily show one main problem. This shows up during the initial priming stage. In the main chamber, the air bubbles may get displaced by the water, and cause water cavities.

These end up being quite problematic to deal with, but only last for a few days when first being used. The best part about this issue is that they end up fading away quite fast, making it easy to deal with.


Q. What are the benefits of a canister filter?

They provide very efficient filtration, have filter media versatility, easy to set up and are very reliable for long term use.

Q. Do you need an air pump with a canister filter?

Aquariums require the water to not remain still, and always be in a constant flow. If your canister filter can create enough of a flow in the water, you will not need to invest in an air pump.

Q. How often do you need to clean out a canister filter?

When it comes to how often to clean a canister filter, it depends on the environment of your aquarium, but on average you need to clean a canister filter around every 2 months.

The Takeaway

Canister filters are one of the best filtration systems out there, due to their great filtration effectiveness and reliability. So, if you are thinking about getting one, do look to get the best canister filter out there for your own tank. This can depend on various factors, which you need to research on meticulously. Have a great day, and find the best one for yourself!

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