Ask any expert aquarist or fish owner, they will reply that opting for the canister filter for their aquarium is one of the best decisions they have made in their fish keeping journey. The canister filter is suitable for freshwater, planted, and saltwater aquariums.

However, when you 1st use the filter you might want to know how to clean a canister filter and the cleaning frequency too. It is important to allow the canister filter to work effectively to keep the aquarium healthy and fish-friendly.

As your ultimate aquarium friend, today, I will discuss the cleaning steps for the canister filter. Also, I will explain how often to clean the filter and the factors that affect the canister filter cleaning frequency.

How often to Clean A Canister Filter?

For an aquarist, knowing how often to clean the canister filter is a key question. When you indeed want to know the cleaning period, you have to understand that different canister filters will have different cleaning frequencies. It depends mostly on their working procedure and fish density of the tank.

For instance, the Fluval canister filter is different from the Eheim filter. Thus, they both have different necessities for cleaning.

The key is to know when to clean the filter media separately and clean the filter itself. The good news is that a canister filter will always warn you when it needs washing and maintenance. Some of the critical signs for cleaning include-

  • When the aquarium water turns muddy, cloudy, or has a bad odor
  • When you notice a higher amount of ammonia or nitrate disposal in the aquarium
  • If the canister filter media or tubes get clogged
  • If you observe debris or other waste particles in the water or inside the filter

In general, you should clean the canister filter at least once every 3 to 5 weeks for its better performance. Also, you have to change the screening media according to their individual schedules recommended by the manufacturer.

How To Clean A Canister Filter & How Often To Clean It

Factors Affecting the canister Filter Cleaning Frequency:

You should clean the canister filter regularly to keep the fishes in a healthy state. Otherwise, the filter may get clogged with debris and cause infectious diseases to your favorite fishes. Once it starts contaminating the water, you can really get pissed off with its performance. Henceforth, you should know the factors that affect its washing period.

  1. Fish density:


The first factor to consider is the number of fishes and aquarium size. If the fish tank has a higher density, you have to clean it more frequently. The cleaning interval will increases with less fish density on the fish tank.

Since more fish means more wastage inside the tank, the cleaning interval reduces considerably.

  1. Planted or unplanted tank:

The planted aquarium will need more cleaning than an unplanted tank. You must remember that a canister filter is the most useful for planted aquarium. Since plants just like the aquarium fishes will produce more wastage, you have to clean it more frequently.

The unplanted tank can be cleaned less regularly. Also, the number of plants will determine the cleaning regularity.

  1. Filter Media types:

The type of filter media a canister filter has will largely control its cleaning interval. Similarly, the type of filters your aquarium has determines the cleaning and maintenance regularity. For instance, if you already have an HoB or Hang on Back and sponge filter for the aquarium, you need to clean the canister filter less frequently.

How to Clean A Canister Filter in 10 Easy Steps

So, I hope you now have a clear idea of how often to clean the canister filter. And you are excited to know the cleaning steps, am I right?

I guess, I am.  So, here I present you the easiest steps to clean the filter quickly and effectively. I will start with the things you will need for the cleaning process. It includes-

  • Scrub pad
  • Sink or hose-high pressure
  • Q-tip
  • Towel
  • Toothbrush
  • Bucket of fresh aquarium water

Once you have all the cleaning items ready at your disposal, you can begin the washing steps for the canister filter.

Step 1: Preparing the canister filter

You can’t just begin the canister filter cleaning right off the bat. You have to prepare the filter for it firstly. You must begin with switching off the filter. Find the power outlet and unplug the filter cord safely.

Next, inspect the filter’s outflow tube. When the filter is turned off properly, you won’t see any water flowing through the tube. It means you can now proceed to the next step. Now, you will have to switch off the filter valves. You have to move the valves in the horizontal position to turn them off accurately. Don’t overturn the valve. Otherwise, you might damage it.

Turning off the valves will prevent water spillage when you unscrew and remove the filter for cleaning. It saves you from additional messes during the maintenance process.

Step 2: Unscrew and move the canister filter

At first, find the threaded pipe and the locking nut on it. Use your hands to gradually unscrew the nuts. You don’t need screwdrivers for it, but you can use them if you wish. When the nut gets loosened, the remaining water inside the motor housing will come out of it. The water amount isn’t much but you should be prepared for it. Otherwise, it may ruin your dress. I recommend you use a small bowl to collect the water.

Once the water drains out properly, remove the filter from the aquarium. Then, place it in the kitchen sink or outside the home. The idea is to place the filter in a place that you don’t afraid to get wet. I mostly use the kitchen sink since it is the nearest place to my aquarium.

Step 3: Remove and disconnect the motor housing

The motor housing is connected with the canister filter with screws and locks on four corners. You have to release all these locks to remove the housing. Once the locking nuts are loosened, gently dislodge the housing from its locking positions.

Since it runs down the risk of minimal water spillage, I use to lay an old towel around the canister filter. It soaks the water and prevents unnecessary water spillage.  Also, you can allow the water to drain out thoroughly to avoid any mess.

Step 4: Removing the fish bowels

This is a crucial step since you have to remove the guts from the filter without disturbing the biological filter. Carefully remove all the filter trays and other parts from the canister filter except the biological filters.

Make sure the biological media containing the tray remains submerged in the filtered water. Otherwise, the beneficial bacterial colony for the fishes will soon vanish from the filter. And you must know that a bacterial colony needs at least one week for formation inside the biological media. So, you must be cautious during this filter removal.

Also, the biological media must remain submerged throughout the entire cleaning process of the canister filter.

Step 5: Cleaning the filters

Now place the filter trays under the running water of the sink or hose. Turn on the tap in its full force so it removes the maximum wastage and debris from the filters. Then, use the scrubber pad to wash off the trays and filters properly.

Also, use an old brush to reach the tiny holes and corners on the trays for effective cleaning. Once you brush the filters it would remove the algae and gross from it. Finally, use a high-pressure hose to rinse off the trays properly.

It will make the filter trays neat and clean and up for another few weeks of use.

Step 6: Remove and clean the impeller

An impeller is housed with the motor and helps running the motor efficiently. If you don’t clean the impellers, they would stop working due to debris accumulation and resistance on it. The impeller is usually connected with the motor housing through a ceramic shop. Since the ceramic is fragile it can break apart easily.

Thereby, remove the impeller slowly and without applying too much pressure on it. Then, use the running water to rinse off the gunk on it. After that use the old brush to give the impeller a thorough cleaning and finally, rinse it off in high-pressure water. Also, clean the parts of the impeller and the motor housing.

It helps the canister filter use less power while ensuring the best filtering performance.

Step 7: Clean the impeller holes

Next, you have to clean the impeller holes properly. Since these holes are extremely tiny, you would have to use a Q-tip for them.

Don’t know what is a Q-tip? Well, it is nothing but the regular cotton swab we use. The holes of the impeller often become clogged or greasy due to gunk accumulation. Put the cotton swab inside the holes and clean the gunk from them. When you clean the gunk from the holes, it considerably reduces the chance of a canister filter malfunctioning.

Step 8: Removing the biological filter

You have to clean the canister as the last step of cleaning it. But for this, you have to remove the biological filter firstly.

Prepare a bucket full of aquarium water at first. Then, remove the biological filter tray from the canister. Then, place it ASAP on the aquarium water-filled bucket. It helps the helpful bacterial colony thrive and not get vanished. You have to work swiftly during this removal process.

Step 9: Cleaning the canister box

Although we know the canister filter by its name, it is actually the canister that accommodates different trays with filters on them. When you clean the trays, it is a good idea to clean the canister itself. Once you have put aside the biological filter tray in aquarium water, put the canister under the high-pressure hose. Rinse it off properly with the high-pressure water and scrub the corners off to remove the tiniest debris from it.

Make sure there’re no algae residuals on the canister walls. Also, don’t forget to rinse off both the interior and exterior of the canister filter. It will give you a premium service from the filter.

Step 10: Assemble and switch on the filter

Now, you will have to reverse the cleaning process. At first, attach the impeller with the motor housing. Then, insert the filter trays inside the canister. You must mount the biological filter lastly and make sure it remains submerged in water.

Then connect the motor housing and reattach the entire filter to the aquarium. Finally, turn on the valves on the threaded pipe to allow the water to flow through the tube. Once all the connections are made secure, connect the canister filter power cord with the wall outlet. The canister filter should start pumping water to the filter box from the aquarium within a few seconds.

Frequently Asked Questions

How frequently should I clean the saltwater canister filter?

Saltwater aquariums have a high amount of algae formation. It is also susceptible to ammonia, nitrate, and phosphate. The saltwater canister filter needs more frequent cleaning due to the presence of such a high amount of marine elements. I recommend you clean the filter for marine or saltwater once every two months.

Does the Marineland canister filter need more frequent cleaning?

No, a Marineland filter doesn’t need more frequency in cleaning. Likewise, every standard canister filter comes with all three types of screening media. You should clean it likewise any regular canister filters once every four to six weeks.

Final Words

So, here we have the details on how to clean a canister filter. The cleaning process is straightforward but it is time-consuming. So, be prepared to invest some time to clean the filter. Nonetheless, you should clean the sink and your hands properly after connecting the canister filter. It is vital since the filter trays will contain huge debris which may affect your health if not removed swiftly and properly.

Once you regularly clean the canister filter, it helps your fish strive inside the aquarium healthily and happily. Happy fish, happier you!

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