Canister filters have been popular among aquarium keepers since they rolled the first version out and found to be more efficient than previous methods in keeping large amounts of water clean and livable in almost all the fish tanks.
Are they better than other methods? Are they for various types of tanks? Are some models better than others? What makes one canister filter better than another?
I hope this article can provide thorough information about canister filters and help you pick out the one that would help you reach your aquarium goals. We’ve even consulted with a few of our aquarium enthusiast friends to come up with a list of top-rated canister filters to get you to look for one of your own.
Aquarium Filters 101
Every aquarium enthusiast knows the importance of a clean tank and pure water on the lives of their precious fish friends. Most times, water quality spells the difference between the success and failure of an aquarium.
Knowing this, they go to great lengths to preserve the water quality to keep their tank in the best condition, and that means using the right equipment — from lighting to heating, to the plants and filtration systems.
All aquariums need some filter. However, strictly, aquariums don’t need to have a mechanical or chemical cleaner to be a right home for fish. Some fish do just fine in a simple bowl of water, with nothing but gravel, water, and some plants.
Filtration happens through three methods: biological, mechanical, and chemical. The essential type of filtration, the biological, is also the easiest and cheapest to set up for your fish. All you need are plants to set up in your tank, plus a few bottom feeders, even a snail or two.
Biological filtration decomposes the waste products that fish naturally produce. When left unchecked, these waste products become toxic ammonia that could kill off all the life in your tank. Biological filtration breaks these chemicals down into harmless essential elements.
Mechanical filtration, also known as physical filtration, removes more significant pollutants such as dead leaves and uneaten food from the water before they decompose and pollute the water. For you to do this, let the water pass through porous media of the filter to catch particles that would otherwise contaminate the tank.
The better setup of this filtration system makes use of different layers of media, going from coarse to more excellent material to maximize efficiency and make sure that the filter can go longer without cleaning. An aquarium canister filter setup, for example, even allows you to choose which media you can use, giving you better control over how much time you need between cleanings.
Finally, chemical filtration removes naturally occurring toxic chemicals such as ammonia, dissolved organic matter, and even heavy metals through the use of activated carbon or resins.
It’s important to note that chemical filtration is never a long-term solution for your tank. It’s best used for immediate and short-term treatments such as treating tap water before loading the same into a container, and for removing medicine residue after the treatment period for your fish.
Filter for Your Fish
Although it is unnecessary to have an additional filtration system on your tank, many experts and hobbyists recommend installing one as an added step towards creating a healthy environment for your fish. As filtration goes, you can’t over-filter, so this additional step is a harmless extra and a virtual lifesaver for your aquatic pets.
Without a filtration system, your tank’s ecosystem can get overwhelmed, and harmful bacteria can make the water toxic for your beloved fish.
Look for signs that your previously healthy aquarium has become toxic. If there is an unpleasant smell in your water, or if the water is cloudy, that’s a bad sign.
Watch your fish, too. Are they sluggish and droopy? Are they spending too much time at the bottom of the tank instead of swimming?
Also, check for moss or algae. A little in the nooks and crannies of your tank is fine, but if there’s an excessive buildup of these organisms, they could well be sucking out the oxygen the fish need to survive. They are also poisoning them with the waste products that they naturally exude.
To prevent these and just as a safety measure, most aquarium owners will opt to install a filter. They recommend it too, especially for people who are seeking to breed their precious pets and for those who are beginner aquascapers.
The most common and most recommended method is, luckily enough, the easiest to set up and more or less the most affordable alternative. We are speaking of mechanical filtration.
All you need for a mechanical filtration system is a pump, intake and outflow valve, and media for the water to pass through. These systems come in a range of builds and materials. We have found that internal canister filters do much more than help to keep the tank water clean.
These canisters also help oxygenate the water by creating surface tension and even provides a place for beneficial bacteria to thrive, if you integrate specific media conducive for it.
Canister Filters
There are eight common types of filters for your aquarium: diatomic filters, trickle filters, fluidized bed filters, sponge filters, box filters, under gravel filters, canister filters, and power filters, with the last four filters being the most popular among aquarium enthusiasts and hobbyists.
Of these, we particularly enjoy the benefits and flexibility of canister filters, like many aquarium enthusiasts around the country.
Canister filters are better suited for tanks with at least a capacity of 40 gallons, and because they are so powerful and they allow for a lot of customization, you can use them for large indoor aquariums that hold up to 150 or more gallons.
We like the fact that you can install most filters like this externally. It means not only that you won’t leave the filter soaking in the aquarium water and potentially upsetting the fish with its vibrations, but you will also save a lot of precious aquarium space for more water, plants, or decorations.
Being located outside the tank also gives the aquarium owner the choice of displaying or hiding the filter in the aquarium stand or someplace similar and out of the way, something that may seem trivial but is an option we’re happy to have.
Canister filters are very versatile. They can provide several filtrations, based on the media in them: mechanical, chemical, and biological.
For physical filtration, canister filters can process more massive amounts of water by forcing pressurized water through filter media. A bio wheel attachment increases the biological filtration capacity of the filtering system, while specialized carbon media is ideal for chemical filtration.
The only downside we can tell you about canister filters is that they can be a little messier and more trouble to clean than other features. However, with the proper aquarium canister filter setup, you will only need to do so every six to eight weeks, which is a small price to pay for a healthier aquarium overall.
They’re comparatively affordable, ranging from $90 to $500. You can use this filter in both freshwater and seawater aquariums.
Best Choices for Canister Filters
While good performers overall, not all canister filters are equal. So we’re sharing a few of our top picks with you hoping you’ll try them out yourself the next time you’re setting up a tank.
One tip is to pick a filter that’s right for the size of your aquarium. If in doubt, go for the more extensive rather than, the smaller option, as again, you cannot over-filter.
So here are our top picks for canister filters, in no particular order:
1. Polar Aurora 3-Stage External Aquarium Filter with Built-In Pump Kit Canister
One thing we love about the Polar Aurora canister filter is that it can come with all the media you need to set up right from the box. It cuts out a lot of the indecision you experience, so it’s great for first-timers.
It also gives a comprehensive range of features, given that it’s more affordable than “premium” brands, so it gives you more leeway to purchase add-ons if you want to. And if you’re on a budget, it gives you a great experience right from the start.
The Polar Aurora is a better choice for larger tanks. It can work with maximum efficiency for tanks as large as 75 gallons, processing as much as 1,000 liters of water per hour.
It has three media trays, which are useful if you want to have several types of filtration available to your tank. It means that you need to select specific media, especially if you need canister filters for saltwater aquariums. However, the versatility these trays offer is something we appreciate.
We find that customization available for users of the unit is impressive because aside from the fact that you can select media to suit the size of your tank, the fish you want to keep, and the water you’ll need, the Polar Aurora has an adjustable spray bar. It benefits your aquarium if you want to control the water pressure that comes from the filter and back into your tank.
Cleanup is relatively easy, especially if you hate manual siphoning. Polar Aurora’s self-priming pump can deal with this necessary evil of keeping an aquarium.
Finally, as icing on the cake, we think that the Polar Aurora could be one of the quietest canister filters on the market. A definite plus points for indoor aquariums — you won’t have to speak extra loud over the filter sound of your beautiful aquarium in your living room.
2. EHEIM Classic External Canister Filter
The EHEIM Classic Canister Filter is one of our favorites for a good reason: it’s one of the most durable, longest-lived canister filters we’ve come across. It’s one of the quietest filtration machines as long as you take the time to set it up properly. We especially appreciate the sturdy stainless steel clamps that affix it firmly to wherever you need it to be.
This model is the most basic for the German-made brand, and while its more professional versions still hit all our buttons, the classic model is one of our favorites for its simple, sleek design, and the essential, almost fool-proof setup.
Small but mighty, it can easily handle most indoor tanks hobbyists and enthusiasts have. Its energy-efficient design can handle tanks from 40 gallons to a massive 300 gallons, which makes it a beautiful thing to have when you have plans to upgrade your tank later on.
We love that we have never had a leaking issue with our unit. It is because it has a Permo-elastic silicone sealing ring located right on the pump head. This placement allows for a tight seal, friendly and easy, even after you've opened it up for cleaning.
This set comes with all the standard accessories: a spray bar, an inlet pipe, valves, a hose, and filter media and sponges. It comes with its media, and that is beneficial if you aren’t sure what the best media for canister filters are. It also comes with the main machine, meaning you don’t have to assemble from scratch. That is perfect for those of us who don’t have as much time or patience to assimilate parts from all over to have a working aquarium by the weekend!
3. Penn Plax Cascade Canister Aquarium Filter
The Penn Plax Cascade looks a little like the EHEIM aquarium filter, but this powerful filter is in a class of its own. This blue beauty is a hard plastic which makes it durable, making it a good investment that can give you many years of use as long as you don’t abuse it.
Another thing we like is the quick and easy setup required for this model. While not a lot of customization is available to users of the Penn Plax basic unit, it makes up with its powerful performance right out of the box. It has a one-touch self-priming function, so all you need to do is find it a spot near your aquarium, assemble and set it up, and it’s ready to go.
This unit that is for aquariums up to 150 gallons comes with a spray bar to help with water aeration and circulation. It is excellent for aquariums with lots of plants!
We especially enjoy the fact that the filter trays on the Penn Plax are spacious, giving you a lot of room to set up the media you like and giving you the filtration your tank needs. Depending on your setup, you can stack the media trays to achieve a multi-stage filtration, even integrating chemical and biological filtration systems.
A unique feature we also like is the two independent 360° rotating taps, giving you a real ergonomic design. It also has a flow rate of shut-off valves that adjust the water flow for you and makes maintenance a breeze.
4. Hydor Professional External Canister Filter
This compact unit is great for cramped spaces and relatively smaller tanks, which refers to anything within the 20-gallon to 150-gallon range. Since it’s an external filter, we appreciate the fact that it’s subtle and discreet, effortlessly blending with the background and taking no one’s attention away from the aquarium itself.
Some of that has to do with how quiet it is. As you can see from our lineup, we like whisper-quiet filters, especially for indoor aquariums.
The inner workings of this canister filter are typical. It features the usual three-step filtration system that lets you integrate all forms of filtration or enables you to choose one type of filtration and run with it.
This tiny but powerful filter requires priming, which is an essential point if you’re a newbie. Push a button, allow the system to prime, then add your fish, and they will thank you for it.
While we can’t say that the price point on this model is as good as the others we have featured so far; the Hydor has much to offer. It’s easy to set up instantly out of the box, and it comes with a set of telescopic intake tubes which give you great control over where you want them to go.
5. Fluval FX6 High-Performance Aquarium Canister Filter
The Fluval FX6 filter makes it to our top picks because of its fantastic capacity, being the filter of choice for tanks containing up to 400 gallons of water. Its multi-stage filtering system features Smart Pump Technology for optimal filter performance, efficiency, and management.
The Smart Pump feature has advanced microchip technology that continuously monitors and optimizes pump performance and even has a monthly maintenance reminder. That’s cool, considering that you might be too busy to remember when the last time you cleaned out your filter was.
The system quickly and efficiently produces healthy aquarium water and is well-suited for large systems that have a lot of organics that need regular removal. That refers to tanks with an abundance of plants or the ones that have larger fish like arowanas, tiger oscars, and Bala sharks.
6. Sunsun Hw304B 525GPH Pro Canister Filter Kit with a 9-watt UV Sterilizer
You might have heard of the Sunsun Canister Filter before: it’s become a popular choice with hobbyists. It has a high price point and gives excellent value for money—a reasonable investment for any aquarium owner who wants to start small and eventually upgrade.
The Sunsun HW-304B 5-Stage External Canister Filter works for both freshwater and marine aquariums up to 150 gallons. Its four flexible media trays take any filtration media. Sunsun has its bio-balls, activated carbons, and ceramic rings.
The filter’s built-in 9-watt UV sterilizer is the perfect tool for keeping bacteria at bay and eliminating algae spores that might overrun the tank. It serves as a powerful deterrent to diseases brought about by bacteria in an aquarium that can persist even without clear indicators such as cloudy water and toxic nitrates.
It is quick to assemble, and as long as you keep the manual around, you can make minor tweaks to make the filtration system perfectly customized to your tastes and the needs of your pets. It’s also quiet that made it one of the best choices for indoor aquariums. You can set it up even where people spend a lot of time with no annoyance or distraction created because of the dull rumbling of filters.
The only thing we didn’t like too much about this filter is that it has a learning curve in cleaning it. It can be a challenge to disassemble it the first time, but there are two silver linings to that: the first is that the filter is so efficient that you will only have to clean it every few months. The second is that after some time, it cleaning it gets comfortable with practice.
Another tricky thing is that you need to arrange the Sunsun media in a specific manner for the canister filter to work at maximum efficiency. That, too, you can quickly remedy by keeping your manual on hand until you get familiar with it, which should only take a short time.
Once you get past these small speed bumps, the Sunsun runs like a dream.