There is no denying that filtration systems play an essential role in aquariums, especially in cleaning and maintaining them. They also come in various types, and one of the most popular is the canister filter.

Most aquarists favor the canister filter for many good reasons. For instance, they operate quietly and require low maintenance.

How does a canister filter work? If you are interested in this topic, you have come to the right place. Scroll down to see more!

What Is a Canister Filter?

canister filter

The canister filter is very common

It is a water filter for aquariums that includes filtration media outside the aquarium. It typically has a pump, filter media, gravity, and lift tube.

This filter allows tank owners, aquarists, or fish keepers to use various filtration methods, including toxic chemicals and fish waste.

You can use a canister filter in many fish tank types, such as saltwater tanks, freshwater tanks, turtle tanks, and custom-made aquariums.

Many tank filters can be submerged in water during use, but that is not the case with the canister filter.

Canister filters are the opposite. To work correctly, you must keep it outside your aquarium and below the water level.

As long as they come with proper filtration media, canister filters can deliver water filtration of all kinds, including mechanical filtration, chemical filtration, and biological filtration.

How does A Canister Filter work?

canister filter working

The mechanism of a canister filter is simple

The canister filter has a simple structure, and so does its mechanism of action. Its operation process basically the following three steps:

Step 1: Draw the Water

It will start by drawing the water outside your aquarium utilizing one lift tub.

It then passes the water to a pressurized canister that includes various filtration media that clean the water inside the canister.

The direction of the water flow may vary depending on your chosen filter model and the brand. This direction might be from bottom to front, top to bottom, back to front, outside to inside, and more.

Step 2: The Filtration Process

After the water is drawn out of your aquarium and goes inside the canister, a pump will push it to the part of this canister where filtration occurs. The filtration process refers to the tank water going through various filtration media.

The filtration media would deliver different kinds of filtration, including chemical, mechanical, and biological filtration. It depends on the filter media you use with your canister filter.

Step 3: Return the Water to Your Aquarium

After the canister filters the tank water, the pump will push it back to your aquarium. Your canister filter utilizes one water pump to move the water as this filtration system is sealed.

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What Components Does the Canister Filter Include?

A Canister filter includes the following main components:

  • Motor
  • Tube system
  • Main chamber


This part will create pressure on the water, making it flow. Its power also significantly affects the filter time.

Cartridge (or Main Chamber)

The cartridge or main chamber is the most important part. It is where the water is pumped in, and the entire filtration process takes place.

It will contain filter media which is responsible for the filtering process.

Tube System

A Canister filter consists of two tubes: an input tube and an exit tube. Those tubes connect to the main chamber. The water will flow through them.

How to Maintain a Canister Filter?

You will have to take more effort into maintaining one canister filter. It includes cleaning the cartridge, changing the filtration media, and more.

The complexity of maintenance depends upon some factors, such as the size of your tank and the level of waste particles filtered.

How Often Should You Clean Your Canister Filter?

We recommend cleaning your canister filter every eight months. However, if your aquarium is too crowded or too large, you should clean it every three to four months.

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Should You Get a Canister Filter?

This filter is worthy of consideration if you value your aquarium environment’s longevity and overall health.

If you want to keep any messy or large fish, such as eels, cichlids, Oscar fish, or goldfish, the canister filter will be one of your best bets.

Are There Known Problems With The Canister Filter?

The most common problem for this filter is tube leaks in the external plumbing.

What Are the Cons of Canister Filters?

  • This filter is typically more expensive than other common filters.
  • This filter is one of the most challenging filters to maintain.
  • This filter can cause leakage.

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What Are the Advantages of Canister Filters?

  • It is more efficient than many other tank filters.
  • Work well for bigger fish aquariums.
  • It is possible to store more filtration media.
  • You can pick the media that works best for your aquarium.
  • Different media allows you to handle different water problems like nitrites or ammonia.
  • It helps you lower the nitrate level in your tank water.
  • It can filter a large amount of water in a shorter time.

 What Features to Check for a Canister Filter?

When buying a canister filter, you need to check the following features:

  • Media.
  • Spray Bar.
  • Power of the filter.
  • Noise while operating.
  • Ease of maintenance and cleaning.

When Should I Invest in a Canister Filter?

large aquarium

You should invest in a canister filter if you own a large aquarium

This filter is utilized for large aquariums or fish tanks. Before buying a canister filter, you should consider if you require this filter for your tank.

Investing in this filter is unnecessary if your aquarium is 30 gallons or less.

On the flip side, it is wise to buy this filter if the size of your tank is more than thirty gallons or too crowded.

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The Bottom Line

As an aquarist, you should know how a canister filter works and the strengths and weaknesses of this filtration system. That way, you can determine if you use this filtration system or consider something else.

Thanks for your time!

Alex is a pet freelance writer and editor with more than 10 years of experience. He attended Colorado State University, where he earned a Bachelor’s degree in Biology, which was where he first got some experience in animal nutrition. After graduating from University, Alex began sharing his knowledge as a freelance writer specializing in pets.

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