9 Best Canister Filter for Your Aquarium (2021 Reviews & Buying Guide)

If you own an aquarium, you may want to consider getting the best canister filter for it as well. This is especially true when you have a medium-sized or large aquarium since a canister filter can work very efficiently with large volumes of water. You can try to find the best canister filter for a 240-gallon tank, though some are small enough to function efficiently as the best canister filter for a 20-gallon tank. 

Depending on your canister filter setup, the filtration can be physical (against dirt), chemical, or biological (against microorganisms in the water). You just have to put in the right filter media for the job you have in mind. 

Of course, it also matters greatly that you get the most appropriate canister filter for your tank. To help you with that, we’ve compiled 9 of the best options you can pick from in the market today. These excellent models have received rave canister filter reviews from other experts and hordes of customers. 

9 Best Canister Filter for your Aquarium

Fluval External Filter (06 Series)

Available in several sizes, the new Fluval Canister Filters offer new convenient features along with a more powerful motor. It’s very user-friendly, so the setup, customization, and the maintenance are also much easier. 

Though the motor is more powerful, this isn’t really very noisy at all. This is due to the precisely engineered bearing that minimizes the vibration of the impeller. There’s a cover as well to smother the noise. 

This features large capacity pre-filters that can filter out a lot of debris. You’re also able to set up chemical and biological filtration. 

The maintenance is easy as well due to nice convenient touches. The AquaStop valves let you stop the water flow without needing to disconnect the hoses so you don’t have leaks and a wet mess. You’re able to change mechanical media quickly, as you can lock the motor housing in place in no time. You can even prime instantly, so you won’t have to siphon manually. 

This works very well, and quite a few turtle owners consider it their best canister filter for turtles. The setup is very easy, with plenty of YouTube videos for you to consult. It’s able to clear out the icky mess in a 40-gallon tank into a clear panorama in just 2 hours. 

Still, take care of this one properly so it works fine. You have to install the impeller cover by exerting firm pressure on the 2 sides of the top to secure it. Otherwise, it’ll just fall off. 

Sure, Fluval can replace even the entire unit if there’s a problem, but the customer support people will want you to send them back your current unit. That’s just too much hassle. 

Read full review of Fluval External Filter (06 Series)

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Fluval FX6 Canister Filter

This is for the 400-gallon tank, though it is only 21 inches high so it’s likely to fit under your aquarium. The filter circulation offers 563 gph of water flow, while the baskets are designed to increase filtration efficiency by eliminating water bypass. 

The SmartPump tech uses a circuit board to monitor the pump continuously. It always checks the speed and force of the impeller to make sure it’s running properly. This tech also controls the self-starting feature. It also removes the air that can build up or enter into the filtration system. The pump will pause every 12 hours to let the air escape. 

You’re able to stack up to 5.9 liters of media in the baskets in the way you want, and each basket has a foam insert lining that works as a mechanical pre-filter. 

What you have here is a canister filter that starts quickly, with a huge bucket of filter media and an extremely strong motor. It can work reliably for years, without having to repair anything.

This particular 400-gallon model, however, is huge. So maintenance won’t always be easy. The motor may be even too powerful for some people, especially when you have guppies and jewel cichlids. You can end up with bay fishes in the filter. 

Read full review of Fluval FX6 Canister Filter

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Penn Plax Cascade Canister Aquarium Filter

This is another series of canister filters for various sizes of fish tanks. The Cascade 500 is for a 30-gallon tank, while the Cascade 1500 is for a 200-gallon aquarium. 

Let’s take a closer look at the middle of the pack, which is the Cascade 1000. It’s meant for up to 100-gallon tanks, and for that volume the water flow is 265 gph. The 2 flow valves rotate 360 degrees, to make it easy to maneuver even in tight tank cabinets. This comes with a push-button primer, which you will need to press a few times to prime the filter. 

This gives you 3 media baskets as well. You can use a coarse sponge for biological filtration, a floss pad for fine particulates, and active carbon media to remove impurities and toxins. 

Each canister filter uses 4 locking clamps to make sure of a watertight fit, along with a motor head with an integrated O-ring. 

This doesn’t really act very quickly, especially if you use it on truly stinky unfiltered water as a test. In 24 hours you will find a big change, but to make the dirty water crystal clear will take a week. You’ll still need a few days after a week to get rid of the smell. With water as bad as this, it took only 3 weeks for the next filter change and a few days after that, you end up with crystal clear water. 

Yes, it’s an unfair test, but it sure worked very well considering the dire initial water quality. It’s also accurate that the Cascade won’t ever let your water get that dirty. If you start with nice clear water to begin with, this system sure won’t let you down. 

We checked the bigger design and they all worked fine, with the Cascade 1500 offering 5 trays for your media. Even at this size, it works very quietly. The setup is easy with no leaks. Some do have trouble priming this, but you can solve the problem by pushing the primer button several times very fast. 

Read full review of Penn Plax Cascade Canister Aquarium Filter

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EHEIM Classic External Canister Filter

This filter comes in different sizes, with an option for a 40-gallon and a 66-gallon tank. But let us take a closer look at the largest which is meant for a 92-gallon tank. 

It gives you a 164gph flow rate along with different types of media for mechanical and biological purification. You have porous glass balls for your bio media, several ceramic rings for mechanical filtration, and several types of sponges. 

It works extremely well especially for the price, and maintenance is no problem. It’s very quiet too, though a few units may develop a rattling noise. But you can fix that with food-grade silicon grease to the ceramic shaft. 

This comes with a white circular polishing filter pad, which can be so fine that it is very quick to get clogged with junk. That can then reduce the water flow and the water can turn yellowish. To fix this, take out the polishing pad and just put in a second coarse filter pad instead. 

Read full review of EHEIM Classic External Canister Filter

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SunSun HW-302 Canister Filter

This is good for a 75-gallon aquarium, especially with the terrific 264 gph flow rate. You have 3 media trays to use, which you can then set up for mechanical, chemical, and biological filtration. There’s also an adjustable spray bar so you can set the output flow from the filter. 

To make things easier for you, this has a self-priming pump. Routine maintenance is also easier thanks to the single valve disconnect. 

This is an affordable model with a simple design, but it also simply works. It’ll keep your tank water clear while it works silently. 

Just don’t manhandle it, as it’s affordable due to the use of plastic parts. The intake mesh may also be too large for shrimp and loaches. You may want to bury the bottom part of the filter in sand to prevent any risk to your fish. 

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Hydor Professional External Canister Filter

This offers canister filters for tank sizes ranging from 20-gallon to 150-gallon. This is very affordable compared to some other brands, but it works just as well as those more expensive canister filters. 

The setup is very easy and consists of only a few simple steps. You can then press the priming button a few times, and when the water gets into the chamber you can turn the canister filter on. 

You’ll notice right off that it’s very quiet, and it’s so silent that you may find yourself looking it over to check that it’s actually working. Then you may realize that the flow rate is quite powerful. For tanks measuring 60 to 100 gallons, you need the 350 model, and this gives you 280 gph. Finally, it is extremely effective in what it’s supposed to do. It just cleans and filters the water beautifully. 

Even the maintenance is simple with just a few steps. You just first close the inlet valve while the pump is still running. Wait a few seconds, and then close the outlet valve. Unplug the pump and remove the hoses. These steps mean you don’t spill a mess of water. 

Just use tank water to rinse the ceramics, since clean water will lose the biologics. You have to rinse out the filter media every 3 months, and you should replace the white filter media at the same time. 

Read full review of Hydor Professional External Canister Filter

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API Filstar XP

This brand has been around for the last 50 years, so they know what they’re doing. The available sizes include 45-gallon (250 gph), 75-gallon (300 gph), 175-gallon (350 gph), and 265-gallon (450 gph). Each model is guaranteed for 2 years.

The filtration here works extremely well, with a 3-stage process. It can accommodate mechanical, chemical and biological media, with baskets able to hold 4 different media pouches each. 

The startup is easy with the self-priming feature, so it only takes a few seconds. You won’t need to re-prime either, because of the innovative anti-airlock system. Once it gets going, you’ll notice that it’s very quiet. 

The maintenance is simple as well as it’s quick to disconnect. There’s a centralized control system for all the functions to remove the canister without losing the prime. You also won’t have any accidental flow issues during the maintenance because of the self-locking water shutoff system. 

The guarantee for 2 years is perhaps the only worrying factor. That’s because previous versions of the API Filstar XP typically lasted 8 to 10 years. Nowadays, the more recent models last for only 4 years or so. 

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Cobalt Aquatics 26000 Ext Canister Filter

Now this is one unique canister filter, as it features an innovative inline pump. The pump can continue running even while you’ve disconnected the canister for your maintenance. In fact, you can put it below or above your tank, and it doesn’t need priming at all. 

This comes with 4 preloaded media chambers for your filtration needs. The sponge filter is at the bottom for mechanical filtration. The second level houses the activated carbon for chemical filtration. Next up us the set of ceramic rings, which work for your biological filtration needs. Finally you have the water polishing stage with the fine finishing pad. 

However, you’re not limited to this particular setup. You can stack your filter media in any order you want and you can use any media type. It’s very quiet, and it’s very easy to clean and maintain as well. 

The accessories that come with the purchase are of relatively cheap quality, There are no clamps for the hoses, and you’ll find it difficult to secure the intake and outflow hoses. There are no bags for the ceramic rings and for the charcoal. 

The pump is also external, and for some people this makes the setup a bit more complicated. But you can reconfigure it to work in the tank, as Cobalt itself recommends, and the setup is much better. 

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SunSun Hw304B 525GPH Pro Canister Filter Kit

This particular model works for up to 150-gallon tanks. Even that size can be dealt with by the powerful 525 gph flow rate. As this is a kit, your purchase includes 4 media baskets, a coarse pad, 4 white filter pads, and a 9W UV. You also get a pound of premium filter carbon, a pound of ceramic rings, and a set of bio-balls. 

It’s quite easy to use, especially with the self-priming pad. Your tank should really be clean with this setup, since you have a powerful flow rate plus 4 media baskets. With the UV, you’re also able to deal with algae.

The UV, however, has a downside. It’s a bit too powerful, and it can damage the plastic parts of the tray. You may not want to use the UV too much unless you have algae issues, or else you’re going to need replacement trays. Suspiciously, they’re also now available online. 

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Frequently Asked Questions

How does a canister filter work?

A canister filter is a filter for an aquarium. It takes the water in the tank through an intake valve, sieve, or tube and then runs the water through the filter media located in a pressurized canister. The filtration method can remove germs, dirt, or chemicals in the water, depending on the kind of filter media you have set up in the canister filter. 

The canister then pumps out the tank water after it has been filtered. As the whole canister system is sealed, it uses water pumps to move the water through the system. Usually, an integral water pump is built into the base or in the cover of the canister. However, there are some models that need an external water pump to run separately. 

What are the maintenance requirements for your canister filter?

You should really read the manual for the specific maintenance requirements, as these will change depending on the particular canister filter model you have. 

In general, however, you have to maintain the filters you’re using. Since they will eventually get dirty filtering out all the filth in the water, you will either have to clean the filter media to reuse them or replace them altogether. 

If you’re going to put in medication inside the tank to treat your fish, you also have to remember to take out any carbon you might be using in the tank. Once you’re done medicating, however, you can put the carbon back in as it will eliminate the medication in just an hour or so. 

Every now and then, you also have to clean the pump and the tubes in your canister filter. This isn’t hard to do, as you can go to a pet store and buy an aquarium tube cleaning kit for this task. 

Why not use a power filter instead?

If you got a very affordable aquarium kit, it may come with a power filter as well. This may also be called the overflow filter or the hanging filter. It works well enough in filtering particulates, and it’s not bad as a biological filter. But it’s not really good enough for chemicals in the water. If you want a better filter, you may want to go with a canister filter instead. 

A typical power filter comes with certain drawbacks that explain why it’s usually so affordable. One reason why it’s not the best is its inefficiency in design which can cause the filter to draw in the water that they’ve already filtered, back into the tank. 

The surface area of the water also increases a lot when it’s returned, so you lose water through evaporation. Water also evaporates more because to mount this type of filter, a large area has to be cut from the top of the tank. This opening can also let fish jump out of the tank altogether. 

A power filter also has a lot of fussy maintenance requirements, especially when compared to the canister filter. The canister also returns the water through a spray bar which reduces evaporation. 

Read More: Canister Filter vs Hang On Back (HOB) Power Filters

Do canister filters oxygenate the water?

A canister filter does help with oxygenation, in a way. Stagnant water leads to lower oxygen levels, because the surface water with more oxygen doesn’t move to bring the oxygen to the lower levels of the aquarium. 

The canister filter moves the water through its filtration system, and the resulting water movement can help with oxygenation. 

How long will a canister filter last?

It all depends on the particular model you get, whether you’re talking about the filter itself or the filter media the system uses. The best canister filter models can last for more than a decade, with proper maintenance and replacement of parts. 

As for the media, how long they last depends on what type of media you’re using. Bio media such as sponges can last for a very long time, as you can just clean them periodically. They can work until they fall apart. 

Some filter media needs to be replaced periodically. The carbon normally needs replacement after a month or so. 

Bio-balls or ceramic rings for canister filter?

Your canister filter may include ceramic rings for biological filtration. But you may want to opt for bio-balls instead, as they degrade more slowly.

Is activated carbon good for chemical filtration?

Activated carbon is very effective for this, which is why it’s a popular option. But to control the growth of algae in the tank, you may want to add a little phosphate remover. 

Is the foam that comes with the filter good for mechanical (physical) filtration?

You should have a combo of coarse, fine, and extra-fine foam. That combo gives you the best results. 

How to Set Up Your Canister Filter

If you want your canister filter to work properly, you have to set it up the right way. Particular steps may vary depending on the model you get, so you have to read the owner’s manual for specific instructions. You should also check out YouTube for videos on setting up your particular canister filter, as videos are better for demonstrations.

In general, these are the basic setup steps you have to take. 

1. Check Your Equipment

Once you have your canister at home, you need to have the listing of the parts so you can confirm that everything is with you. You then have to check that each part is undamaged and working properly. You have to check that you have the right type of filter media for your canister, and that they’re undamaged as well. 

2. Prepare the Aquarium

Determine where the best spot is to put in the canister filter. It’s best to place it within a range of 8 inches to 4.5 feet under the water level of the tank. The manual for the filer should have a suggestion for this spot. The tank should be filled up to its maximum level. 

The hosing should have an unhindered path to the tank. Test out the tubing so you know it can reach the tank. There should be no kinks, slack, or loops. 

3. Get the Filter Media Ready

Take out the motor head of the filter then check that all your media baskets are inside. You may have to fill 3 or 4 media baskets, depending on the filter you have. Get your media and arrange them by type, so you can put them in a layer at a time. 

If there’s a gap in the bottom of the filter when you insert the baskets, you may want to use some old ceramic rings to line the bottom. These will diffuse waste that may collect in that area.

4. Put In the Mechanical Filter Media

The mechanical media is generally the first line of defense so you put them in first. That way, they catch the debris and waste that may clog up your chemical and biological filters. Stack the coarse, fine and extra-fine foam from top to bottom in that specific order. 

5. Put In the Bio Filter Media

You can put the bio-balls or the ceramic rings in the second tray from the bottom. 

6. Put In the Chemical Filter Media

There aren’t really any hard and fast rules for the 3rd tray (and for the 4th if you have one). You can install the chemical media in the 3rd tray, or use other bio filter media here. You can put in activated carbon along with phosphate removers. Don’t forget to use a filter bag, as the loose granules of the media can clog up the impeller of your filter. 

7. Ready the Intake

This is the filter component that draws the water from your aquarium. If your filter has a connector to secure the hoses, you can fasten that connector to your aquarium. Then loosen the intake clamp to attach the hose to the filter and to the intake valve in particular. After that, retighten the clamp.

Now run the hosing to the aquarium and cut the hose to a length so there are no loops and slack. Then secure the hosing to the connector. 

There’s an intake tube that lowers into the water, and that’s where you should fasten the end of the hose. The end of the tube should be at least 3 inches from the tank bottom. However, your manual may have a suggestion as to how far you should extend the tube into the water. 

8. Ready the Output

The process here is quite similar to how you prepared the intake. Prepare the connector, attach the hose to the filter, cut the hose to length, and then put in the tube into the tank. The main difference here is that the output nozzle should be at least an inch under the water line but it doesn’t have to go all the way down to the bottom. 

9. Start the Filter

First you need to recheck everything to see that everything is securely connected and in place. The valves should be open to move the water. For some models, it may be necessary to have some water in the canister before you start. If everything’s ready, plug in the filter and get it going. 

Some models have an auto-prime feature, so your filter will run for a while to get the water flowing and to expel the excess air from the canister. Once that’s done, it will run smoothly until you turn the filter off. If you don’t have auto-prime, you may have to press the priming a few times to get the pump going and prime the filter. 

10. Check for Problems

Now you’re done, and your tank water should start getting cleaner. However, you may want to monitor the whole thing for a while to check for any problems. You may hear rattling noises at first, and if they don’t stop you should make sure that there’s no debris clogging any of the components. If the flow rate is a bit slower than expected, you may want to check for any tubing obstructions, and you should tighten the connectors as well. 

How to Clean a Canister Filter

Each model will again probably have a set of cleaning instructions in its manual. However, for most canister filter systems the following steps are generally involved:

Gather Your Supplies

You’ll need the following items:

  • Q-tip
  • Scrub pad
  • Toothbrush
  • Towel
  • A bucket of tank water
  • A nice clean work area

Turn Off and Unplug the Filter

There should be no water coming off the outflow tube of the canister filter. Once you’ve checked this, you can continue.

Turn Off the Shutoff Valves

Do this horizontally until you get to the OFF position. This keeps the water from spilling out later, when you take out the tubes from the motor housing. 

Disconnect the Tubes

You’ll have to slowly turn the locking nut off until it comes loose from the threaded pipe. Water may spill from the motor housing, so get ready to deal with that. After that, set the pipes aside for the moment. 

Take the Filter Out to Your Kitchen Sink

Or you can take the filter to your bathroom or outside. Basically, you want to place it in a place that you don’t mind getting wet. But the kitchen sink will do if it’s near enough to your fish tank. 

Take Off the Motor Housing

You’ll have to release the locks on the 4 sides to take off the housing, and water can again spill out. Maybe you can lay a towel down around the filter beforehand. Take off the housing carefully then set it aside. If there’s still a bit of water in the housing, drain it out first.

Remove Everything Else

This means taking off everything in the filter aside from the trays in which you put your bio filter media. The biological media needs to remain underwater, to keep the helpful bacteria in. You can now clean the rest of the filter. 

Cleaning Time

Rinse the media trays, using a hose or your kitchen faucet. Then use a scrub pad or an old toothbrush to really clean them. You’ll want to make sure you take off the icky algae. 

You’ll also need to clean the filter pads, so hopefully your kitchen sink faucet has strong pressure. 

Take Off the Impeller

This time, you have to be extremely gentle when take off the impeller from the motor housing. You have to be very gentle because the ceramic shop here is very fragile. If you’re not careful, you’ll just break it. If you do break anything, at least you can get replacement parts easily from the fish tank supply store. 

Clean the Impeller

Now clean the impeller carefully. This is an important step, because if you don’t do this you may end up damaging the motor. Don’t forget to clean the shaft and the other plastic parts around the impeller. Use the toothbrush here instead of the scrub pad, which may break the impeller. 

Clean Off the Impeller Hole

You won’t believe how dirty this can get until you see it for yourself. So take your Q-tip and stick it in the hole where impeller sits. There’ll be a lot of yucky stuff along the sides of this hole, and you need to clean them out.

Take Out the Bio Media Trays

You’ll have to remove the biological media trays very quickly, and then if possible you should set it in your bucket of tank water. This prevents you from losing your helpful bacteria. Now discard all the water in the canister filter and don’t use that water again.

If you don’t have that bucket of aquarium water, you have to move extremely fast. Exposure to air can lead to loss of your beneficial bacteria. 

Clean the Canister Itself

You can just spray it with high pressure water to get rid of any debris and algae. Then you can finish cleaning it off by wiping it down with a clean cloth. 

Now you’re done with the cleaning part. Afterwards, just put everything back the way it was in the canister. 

Turn On the Shutoff Valves

Once the valves are in the ON position, raise the front locking bracket up so the canister can fill back up on its own. Once the water level hits the motor housing, lock the bracket back in place. 

Now you’re done. Plug the filter in, prime it up, and get it going. 

Buying Guide

How do you pick the best canister filter 2019 has to offer? You should read the product descriptions and check the various canister filter reviews written by experts and customers. More specifically, focus on the following considerations:

Tank Size

The right canister filter depends first on the size of your aquarium. Some canister filters are designed for huge 240-gallon tanks, while others are meant for much smaller aquariums. If you’re unsure about your choices, go for the larger models. It’s not really a problem if you over-filter the tank. But if the filtering capacity is inadequate, you can end up with dead little fishies. 

Flow Rate

This refers to the movement of the water through the canister, and it indicates how quickly it can filter your water out. This is expressed in GPH or gallons per hour.

You’ll need to get a high GPH ratering in accordance with the capacity of your tank.

Filtration Effectiveness

The more marine life you have in your fish tank, the greater filtration capacity you need. So you may want to get more stocking levels (baskets) and several different types of filter media. The best canister filters can have as many as 6 baskets, where you can put in 3 different filter media types. 

Ease of Use

You should read the canister filter reviews to find out how easy it is to set up, use, and maintain the canister filter. Of course, the easier it is the better value you get for your money.


Also check those reviews to find out about the quality of the canister filters. You’ll want a system you can rely on for a long while. 

Final Words

Among the many types of aquarium filters you may be able to use, a canister filter is simply among your best options. The best canister filters can deal with even larger tanks or large fish that can make a lot of mess. 

With this, you’re able to customize your filtration system so you can find the best arrangement of mechanical, bio, and chemical filtration media. The high water flow makes sure it works very efficiently, and it even helps in oxygenating the water. 

Just make sure you set up your canister filter properly, or else you’ll end up with a lot of problems (and maybe dead fish). You have to maintain it properly as well, with regular media replacements and filter cleanings. Watch YouTube videos made by users of your particular canister filter model, so you know for sure how you can take care of your canister filter properly. 

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