5 Most Common Problems with Canister Filters

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Good filtration is paramount for a healthy fish tank. Depending on the species and number of fish, as well as the plants you keep in the aquarium, you’ll have multiple filtration options. If your aquarium has high filtration demands, you might have decided to opt for a canister filter. Canister filters are a great high-end filtration option for freshwater tanks.

They can also work pretty well for fish-only saltwater aquariums. These filters are reliable and highly efficient. They provide a high-water flow rate and superior mechanical, biological, and chemical filtration. They also don’t have the same vibration noise issues as HOB filters. Finally, they have long-lasting functionality and a simple setup.

However, nothing great comes without some downsides. Despite their perks, canister filters aren’t impervious to malfunction. In this article, we’ll look at the five most common issues with canister filters and their easiest fixes. If you wanted to learn more about the potential canister filter problems and solutions, now’s your chance to do so.

Water Leaks

Water leaks are one of the potential issues you might encounter when running a canister filter. Serious leaks are not that common. If you invest your money in a high-quality filter, most leaks will be because of user error.

Some of the main causes of water leaks include: a poorly fitted gasket or O-ring, damaged gasket or O-ring, broken or weakened clips, unproperly sealed canister, hoses that aren’t tightly attached, and old rubber seals that need replacing.

Proper care and handling will minimize the risk of component damage. Make sure to clean the filter regularly. The rubber seal should also be replaced once every 2 years at least. Finally, you must pay great attention when putting the filter back together after cleaning.

Ensure that all the components are tightly attached and sealed. The user manual should come in handy when you have to put the canister filter back together. It will also give you all the tips necessary for proper maintenance.

Impeller Problems

The impeller is a moving filter component located inside the pump. It controls the water flow in the tank by creating a centrifugal force. As the impeller rotates, the movement it creates helps the water push through. Sometimes, the impeller might get clogged, damaged, or overheated.

When this happens, you’ll notice a change in the water flow and filtration rate. To keep your filter running at its full potential, you’ll have to pay great attention to the impeller and pump. Make sure to clean the impeller and the housing every three months.

Waiting too long between cleanings will lead to a buildup of gunk and calcified remains. This will lead to slower impeller movement, blockage, and overheating. If such problems go on for too long, you might permanently destroy the pump.

A clogged impeller can also cause a rattling noise which can become quite upsetting. Besides cleaning the components, you can also apply lubricants such as Vaseline on the impeller shaft. This will reduce the noise and increase the flow rate.

Motor Problems

The motor is the filter component that sets everything else in motion, including the impeller. If the motor is damaged, the filtration rate in the aquarium will be affected even if all other filter components are completely fine. Sometimes, the motor might stop running altogether.

It’s quite easy to detect filter motor problems. If the filter case is hot to touch, the motor is probably working overtime and heating up. It’s even more obvious when the motor turns completely silent. At that point, the filter isn’t running at all.

The most common cause of these issues is clogging. Just like gunk can build up in the impeller, it can also affect the motor. This problem has an easy fix. All you have to do is take apart the filter and clean the motor of any debris inside. If your filter motor is waterproof, you can just run the component under a powerful jet of water. You can also use compressed air or a small cleaning brush.

If the filter is still overheating or not turning on after cleaning, you’ll have to look into buying a repair kit. These are pretty easy to use and they come with clear instructions. However, if the motor problems persist, it might be easier to just replace your old filter.

Clogged Tubes

The tubes help the canister filter circulate water in the aquarium. The problem is that they can get clogged, just like any other component of the filter that’s submerged in water. But because the tubes are static, unlike the motor and the impeller, sediments can deposit a lot easier inside the tube lining.

In a heavily populated aquarium, the tubes will develop buildup and require cleaning at least once every one to two months. Failing to clean the tubes might lead to clogging and obstruction. Unlike the pump and motor, tubes are also usually transparent and directly exposed to light. This makes them a suitable place for algae growth.

Algae clogging filter tubing isn’t at all uncommon. You can avoid this issue by installing grey or dark-colored tubes. Smooth tubes are also preferable to ribbed tubes. The ribbed shape of some tubes makes them very easy to clog but difficult to clean.

You can prevent clogged tubes by choosing darker, smooth tubes and cleaning the tubing once every month. More frequent water changes can also slow down the buildup of gunk in the tubes. Finally, adding a filter sponge on the intake can also help mitigate this issue.

Noise Problems

The average aquarium filter emits a continuous electric humming sound. It might seem distracting at first, but it just blends in with any other background noise in the house, such as computers, refrigerators, and so on. But when the filter isn’t working properly, the noise might become a problem.

Any part of the filter can become clogged or dislodged, but the moving parts are the most likely to cause noise. When moving parts are clogged or misplaced, you’ll get a rattling sound. If you’re dealing with this type of sound, you’re most probably got a backed-up or weakened impeller.

A clogged motor could also cause similar issues. Poor water flow due to blockages can also lead to a buzzing sound, but mostly in static filter components. Buzzing sounds happen when filter media and tubes have an excessive buildup of debris, algae, or calcification.

To solve both types of noise issues, you’ll have to take your filter apart piece by piece. You must clean all the components and make sure to fit them tightly when putting them back in place. Lubricating the moving components will also help diminish the noise.


Most problems you might encounter in canister filters have to do with user error. Poor maintenance and poorly installed components are usually the most probable culprit. Whether we’re talking about impeller, motor, or noise problems, the first thing you should do is clean your filter thoroughly.

Leaking problems are very uncommon in high-quality canister filters. As long as no component is cracked or broken, any leaking is likely to be due to a loosely fitting tube, O-ring, or casket. Overall, canister filters aren’t more likely to malfunction when compared to other types of filters. With frequent cleaning and careful handling, you should be able to solve or prevent these issues.

Author Image Fabian
I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.
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