How Does A Canister Filter Work And What Are The Benefits?

If you have recently bought an aquarium, you might not know that there are tremendous types of fish tank filters out there. It will be impossible for you to keep your aquarium clean without a filter, and it will require a lot of work. You don’t need to stress yourself. I have brought a perfect solution for all of your problems. While searching for the best filter, you might have come across the term canister filter. It is the most popular and loved filter out there. You might be thinking, what is a canister filter? What makes it popular? or how does it work? You will find the answer to all these questions in this article, so keep scrolling down.

What Is A Canister Filter?

If you have just heard the name and know nothing more about canister filters? So, before learning about how it works, let me tell you what the canister filter is. There are many different filters, each with a distinct structure and features. But the one thing they all have in common is the function. All water tank filters are designed to strain out all the impurities present in the water.

How Does A Canister Filter Work

The canister filter is a particular type of aquarium filter, a bucket-shaped machine, having different kinds of filter media in it through which the water is passed so it could purify the water by filtering out all the wastes present in it. It not only removes the physical debris from the water, but it also gets rid of any detrimental chemicals which can damage the health of your beloved fishes.

Components of Canister Filter

I don’t mean it has anything more to it by calling it bucket-shaped. It has a simple structure, yet it carries out a systematic functioning. Many parts of the filter work collectively to filter the water efficiently. The following are the essential parts of a canister filter.

  • Chamber is a cylindrical main body enclosure that provides a space for the filter media. The purification capacity of a canister filter depends on its chamber’s size. The greater the size, the more filter media you can put in it to filter the water.
  • Filter media is the central part of the canister filter, which removes the unimportant and damaging materials from the water. There are three different types of filter media depending upon the type of substance it is filtering out: chemical, biological, and mechanical filters.
  • Tubes are the two pipes that come with these canister filters. One tube brings the water into the filter, and the other takes the filtered water out into the fish tank. These tubes are attached to the inlet and outlet of this filter.
  • A pump is a device that forces water to go out of the filter chamber after passing through the filter media.

The parts mentioned above are just the main ones. Many other parts might not be as big but have some importance in the functioning of this filter. The canister filter has a barrel head with a UV sterilizer on the inside, a dual valve for the output, and one for the input. The filtering component has the media, filter media tray, and a filter compartment cover. There is also a spray bar present to enjoy a few water patterns on the water’s surface.

How Does A Canister Filter Work?


Unlike other filters, you will not see much filtration going in or around the aquarium. This fact might be surprising for you. If you are staring at the box of a canister filter, trying hard to figure out how it works and how to set this up in your tank, then you are at the right place. There will be many videos out there, but reading will make it easy to understand.

The canister filter takes water from the tank and makes it pass through the filter media and then into the tank. This process of taking in and pushing out of water parallels. So, you might not notice the difference in water level. There are two tubes. One has an intake that brings the tank water into the filter with the help of gravitational force and pressure. At the same time, the other tube is attached to the outlet. The pump forces the water to flow through the media and eventually goes back to the tank after getting filtered.

The filtration process is carried out by the different media present in the chamber. The biological media provides an area for the growth of beneficial bacterias, which can clean the environment for the fishes, such as bio balls and ceramic rings. The chemical media is the one that gets rid of the harmful chemicals present in the aquarium’s environment, such as ammonia which can cause the death of life inside the tank. The mechanical media such as sponges and filter floss absorbs all the dirt and waste particles present in the water.

What are the Benefits of Having a Canister Filter?
The canister filter is often seen as the obsolete pinnacle of filtration. It is the most known and the most used filter out there. So, let’s see the pros of the canister filters, which make it such a much admired and recommended filter of the recent era. The following are the pros of canister filters.

  • The canister filter provides mechanical, chemical, and biological media. So these media can purify water by removing all forms of waste and impurities, whether waste material or chemical toxin.
  • You don’t see any filtration going on in the tank. You can easily place it below the aquarium tank. So, it doesn’t ruin the aesthetics of your aquarium tank. The only thing you might see is the inlet and the outlet.
  • The chamber has a lot of space for media, so you can add other media even if you have a small tank.
  • Canister filters are relatively quieter than the other types of filters. So, this can be an excellent option if you have a centerpiece tank in the living room or any public place and don’t want to listen to it running.
  • If you place the inlet and outlet in different directions, you can get better mechanical filtration and flow.
  • The canister filter is versatile as it can work efficiently for both freshwater and saltwater tanks.
What are the Drawbacks of Canister Filter?
The canister filters are undoubtedly one of the best aquarium filters out there, but there are some drawbacks that I have noticed while using some of them. Here are some issues that one might face while working with these filters.

  • The canister filters are expensive compared to other types of water tank filters out there. It is undoubtedly terrific in performance, but mainly canister filters are high-end, especially those that come with a sufficient amount of filter media.
  • The canister filters do require good maintenance. Once you have stopped taking care of it, the condition and performance of the filter will deteriorate soon.
  • The large volume of the chamber is undoubtedly a plus point. But many users dramatically over-filter the chamber, reducing the space for water flow. If the water flow is not proper, your filter cannot work.
  • Whenever you start the filter, whether it is the first time or run the filter after cleaning the filter, you first have to prime it. Priming is when you have to fill the empty filter chamber with water. When you push the button, a loud sound is produced as the water rushes into the room from the tank. You don’t have to repeat this step unless you restart the filter.
  • Canister filters can also face the issue of leaking. If the chamber gets damaged, it can cause water leakage, or any damaged tube or loosened valve can cause this issue.


How often do you need to clean a canister filter?
Well, there is no fixed amount of time for it. It depends upon the size of the tank you are using or the amount or type of life you have inside it. Suppose you have overstocked your tank with high waste-producing fishes such as goldfishes. Then you need to clean your canister filter in about five to eight months. If the filter gets dirty, it loses its efficiency.
How long do canister filters last?
The lifetime of a canister filter depends upon its use and maintenance. If you have given proper care, then it will work efficiently. You don’t have to worry about the functioning of the canister filter if you keep it clean and change the media when required. Most canister filters come with a three years warranty.


If you have bought an aquarium for the first time, a canister filter is undoubtedly the best option. Its maintenance and use do not require any particular skill or effort. It works based on the siphoning principle. It is the easiest to use. The canister filter doesn’t ruin the style of your aquarium, unlike those hand-on filters that don’t seem to go with the tank. The canister filter is placed beneath the tank, gets the water from the intake, and pumps it back to the tank after filtering it. I hope this article will help you understand the working of a canister filter and create and maintain a healthy life for your fish.

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