Water filtration is arguably the most important part of a fish tank’s setup. With all the gear options out there an objectively good aquarium canister filter choice via comparison can be maddening for the newcomer. Should you go for a Fluval canister filter VS an Eheim one? Then again, the brand names mean nothing, unless you take into consideration your setup. What would be the best canister filter for a heavily planted tank setup, for example? But it’s not just that, how about the size of your freshwater fish tank? What would be the best 75-gallon aquarium canister? How about for 90 gallons? Or 125? Is there a good canister unit for smaller tanks?
A quick overview chart of the best canister filters for freshwater aquariums
|Filter Model:||Recommended for:||Best price:|
|1. Eheim Classic 22(XX) Series||10 to 55 gallon tanks||Amazon|
|2. Penn Plax Cascade (XXXX) Series||30 to 75 gallon tanks||Amazon|
|3. SunSun HW-(XXX) Series External Canister Filters||30 to 55 gallon tanks||Amazon|
|4. Fluval (X)06 Series External Filter||30 to 75 gallon tanks||Amazon|
|5. Fluval FX(X) Series Canister Filters||90 to 125 gallon tanks||Amazon|
|6. API FILSTAR XP Series Canister Filters||40 to 75 gallon tanks||Amazon|
External filtration is a must-have hardware in all aquarium systems. But why is that?
Education is power. We need to be aware of the important factors that should play a role in our decision on a canister filter, before making a purchase.
Buyer’s WALKTHROUGH when shopping for a canister filter:
There’s no such thing as an objectively best product. There are only best products according to your situation.
To find out which canister filter will suit you the best you’ll need to consider a couple of factors before making a purchase:
1. Your livestock:
The livestock you keep is 50% of your decision on a canister filter.
- When looking to filtrate a heavily planted tank you’d look for something that will move around carbon dioxide. Yet if you pick a canister filter that’s too strong, the current may tear down parts of your precious aquatic plants. Most LPS corals like a particular current and won’t really spread in their full potential if wrongly positioned.
- The size of your fish also plays a role in your pick. Smaller fish can either get blown around or sucked in by a stronger filter. Larger fish often prefer a slower current. Fish like bettas, angelfish and other long-tailed species can have difficulties swimming in a stronger current. Most bottom dwellers like a current.
- The mess your fish make has the greatest impact on your pick of a filtration system. Goldfish are notorious for the mess they make and require stronger filters. Large 100%-carnivorous fish will produce huge amounts of waste as well. If you plan on keeping a freshwater eel, cichlids, Oscars, or Piranhas a highly-rated canister filter is a must. This in combination with your fish tank’s size will determine the water turnover you’d want to have in your system.
2. Your tank size:
The dimensions of your aquarium will determine how much gallons of water you’d likely need to be turned per hour.
It is usually recommended that you look for at least 4 times of water turnover per hour. But according to your livestock, this number can be scaled up to 7 or 8 (see the previous point).
Different canister filters have different GPH (gallons per hour) / LPH (liters per hour) of water turnover.
The advertised number is usually tested on a tank that only has water in it. No aquascape or liverock. Filtration media is also absent from this test. Depending on the motor of the canister unit, the advertised number may get reduced with up to 60% when you add filter pads, rockwork, plants, and fish.
This is an important consideration when looking up canister filters and comparing characteristics. It is the reason why every experienced fishkeeper will suggest that you buy a canister filter that is rated for twice as large tanks.
3. Manufacturing architecture:
The way a unit is assembled plays a great role in its durability and efficiency.
It also plays a role in the canister filter setup itself.
I won’t go into details (as I’m not that tech savvy), but a good indication here can be the brand of the canister filter. There are brands that have been tested by thousands of fishkeepers throughout the years and eventually stood out.
For example, you can expect a filter that’s manufactured in Germany to last several years more than a cheaper Chinese version. This is not always the case though. I am actually reviewing two Chinese products in this guide because they have proven themselves to me (and many others for that matter).
A well-built filter will have sturdy parts, unsusceptible to breaking or malfunction.
The architecture will also determine the loudness of a canister filter during work.
4. Pumping Motor & its impeller:
The motor of a filter is its heart and soul.
Given that you will only turn the filter off during maintenance, a strong and durable impeller is a must.
All of the filters I am reviewing here have great motors, as expected. The motor is the only moving part inside your unit.
There are two types of motors that canister filters employ.
- One is an epoxy-sealed motor. A particular feature of these motors is that the impeller is positioned upside-down. This in itself is a practical solution to moisture and debris, that can hinder proper functioning. These motors rely on electricity powering a magnetic coil, that in turn rotates the impeller.
- The other type is a motor that’s magnetically driven. Although these motors also utilize a magnetic coil for their spin there are a couple of major differences to be pointed out. One is that these motors are self-priming. Priming is by far the most annoying feature of canister filters. On the other hand, the impellers of these motors are exposed to more debris and may get clogged faster. Nothing to be scared of, as with proper maintenance these motors can actually save you the hassle.
The sealing in a motor is its second most important feature.
Weared out rubber O-rings are the main reason for leaks. Fortunately, replacing them is not something hard or expensive. Here’s a pretty good video on motor maintenance, that I wish more people would see. It’s only 7 minutes long but it will absolutely clarify the basics of how motors work. Watch it and you’ll know what to do when they fail, instead of panicking.
Your device will circulate hundreds of gallons of water daily. You don’t want that water to end up on your floor.
The valves in a canister filter can be the difference between a year-long service and costly part replacements.
Though the models mentioned below all stand out with excellent sealing I am obligated to mention this, in case you decide on another product.
You can’t really establish if a valve is properly sealing the water if the filter’s not running. A good indication of that can be online reviews from REAL buyers.
6. Loudness during operation:
One of the most enticing features in canister filters is how quiet they operate, unlike their HOB counterparts.
However, there are models that will be noisier than others.
This is not to a significant extent as they are all pretty quiet.
Still, if you consider yourself a super light sleeper and you keep your fish tank in the bedroom there are models that will suit you better. Some canisters are virtually silent. I’ve done noise reviews on a couple of filters to aid you in the quest of finding the quietest one.
7. The time it takes to disassemble a unit for maintenance:
This is probably the only overall con of canister filters.
Though MOST of them are designed with the idea to be taken apart easily, it takes time.
When you’re considering a canister filter for your freshwater aquarium you should be prepared for what comes with that.
If you have a quality device and filter pads (as the ones I will describe below) the cleaning should only occur every 2 to 3 months.
But it is time-consuming.
Larger filters will need to be transported outside because they will spit water upon opening the valves (with a few exceptions). And moving around a canister that’s 3 to 4 gallons of volume can be heavy.
I don’t mean to scare you, but rather prepare you, as you may consider this an unpleasant surprise.
Trust me, for the type of filtration these devices provide for your aquarium, the 20 minutes of cleaning are well-worth it.
8. Unit dimensions:
One of the main advantages of canister filters is that they offer plenty of room for filter media.
It’s a blessing and a curse.
Some units can be quite large, something you cannot really tell from their stock photos.
Do check the dimensions in the description, if you’re purchasing online.
It is quite unfortunate to have a filter knock on your door, just to see there’s no place to reasonably fit it in your stand.
It is true that these filters do not spoil the aesthetics of the insides of your fish tank. However, they can be unsightly when sitting in a random place nearby the aquarium.
Do your measures and make sure your aquarium stand can hide the canister filter. If needed modify your stand beforehand by drilling a hole here and there.
9. Power consumption:
If you’re like me, you are likely running more than one tank at home.
Then you’d know that this hobby can make a decent portion of your electricity bills.
Fortunately, some canister filter manufacturers take this into consideration as well.
Eheim, for example, is known to not break the bank when it comes to power consumption.
Though it’s not something that should really weigh on your choice of canister filter I am obligated to mention it.
10. The weight of your wallet:
As a general rule of thumb canister filters are pricier than their HOB or sponge counterparts.
The difference in the price originates from their main advantages over the other types of filters:
- flowrate controllability
- higher water turnover capacity
- very silent operation
- undisturbed aquarium aesthetics
- considerably more room for filtration media
You could probably see that (as I continuously repeat throughout this guide) you get what you pay for.
However, sometimes we just have a set amount of money that we can’t really go over.
For this exact reason, below I will give out recommendations for people on a budget as well. It may not be the perfect case for your tank setup, but it will be the best bang for your buck.
11. Room for filtering media:
A canister filter will offer multiple stages of filtration.
The larger devices will have up to 6 trays for filter media. The more the merrier.
The volume a tray provides will also vary. Some units will be just huge, offering plenty of space for housing beneficial bacteria.
By employing more biological media you can be sure that your freshwater tank remains cycled at all times.
By the way, here’s a quick hack on inexpensive filter floss that will make your water crystal clear within hours. Really great for planted freshwater tanks. It’s worth implementing it every 2 months to absolutely polish your water quality. You can also use the stuff as your sole media for biological filtration.
Employing it more often, however, is not something that I would recommend with a canister filter, because of how fast the filter floss traps small particles. You’d need to clean the filter more often, but if you’re okay with that – go for it (I may just be lazy).
Honest reviews: The 6 best canister filters for freshwater fish tanks
A canister filter guarantees quality filtration and prolongued livestock lifespan. I’m reviewing these units as I’ve found them to be the top performers on the market right now. These are the canister filters that are considered the best for a freshwater aquarium:
1. Eheim Classic 22(XX) Series – Long-lasting
The Eheim Classic external canister filters are manufactured in Germany.
These units have been around for quite some time now.
I can only say they still work perfectly for certain freshwater aquarium setups (according to my experience).
They are not a new model but are being a favorite choice of many fishkeepers to this day.
These filters provide an excellent quality for their price while being easy to maintain (something that’s not often seen with canister filters).
Eheim as a brand holds positions among the best canister filters for small and large aquariums. The 22XX Series (2211, 2213, 2215, 2217, 2260, 2262) have a solidly assembled structure that results in impressive longevity.
It is not uncommon to have an Eheim run flawlessly for over 10 years. And for the price tag, these filters are probably your best long-term investment (for serious fishkeepers only!).
I’ve had the pleasure to own a couple of these throughout my years of keeping fish.
In my experience, the advertised filtration of the units gets reduced the least with adding filter media.
They are really quite and suitable for aquariums that stay in bedrooms.
The German engineers also made sure that you do not break the bank with electricity bills. These filters are well-optimized for 24/7 work while remaining efficient in terms of power consumption. An aspect I find important, as my freshwater aquariums make a significant portion of my bills.Advantages:
- Stunning longevity of the units
- Permo-elastic silicon sealing
- Enormous space for filter media
- Comes with the various useful media upon purchase
- Easy on the maintenance part
- Simple installation
- Really quiet operation
- Overall lower GPH for the price (which can be good for beneficial bacteria)
- The canister is somehow large
- The motor is not self-priming
- The manuals are garbage (just watch a video online on how to set it up)
2. Penn Plax Cascade (XXXX) Series – Most Positive Reviews
The Penn Plax Cascade canister filters have absolutely exploded in the fishkeeping world. They are also top-rated by users.
This is a rather ugly-looking filter that will definitely surprise you (in a good way).
Depending on the model they will have between 2 and 5 stages of filtration. That, along with how spacious the filter trays are, allows us aquarists to be as flexible as we want with our filter media of choice.
Another feature that may win your heart is how this filter is built.
The manufacturers use a special kind of sturdy plastic (unlike other brands) that make these filters very hardy. As small-ish plastic parts are the first to break in a canister filter, this comes off as a huge advantage, at least for me.
The Cascade series are absolutely customizable. You get to play with your desired flow rate and the valves are able to rotate on 360 degrees.
It’s quite easy to install the unit just the way you like it, with no positioning limitations.
If you’re a total novice in canister filters you will manage to set it up from the first time.
The maintenance and disassembly are a child’s play.
Having tested many brands throughout the years, I consider this filter the most novice-friendly in that regard.
You also have the benefit of a self-priming motor. And manual priming is usually the most annoying disadvantage of canister filters.
This, along with an excellent level of filtration.
Another thing I’m thankful for is that no modifications are needed for this filter. The package includes a spray-bar and a spout outlet. From here, it’s only up to you to choose whichever works best for your freshwater setup.Advantages:
- Highly customizable (flowrate included)
- Comes with a spout outlet & a spray-bar
- Up to 5 stages of filtration
- Self-priming button
- Easy to disassemble
- Sturdy plastics
- Straight-forward instructions
- Comes with carbon filtration
- Not all of the water passes through the trays (given the flow rate potential, this is not really an issue)
- Not as long-lasting as other filters
- The handle is not strong enough to carry the unit
- The canister is rather heavy
3. SunSun HW-(XXX) Series External Canister Filters – Cheaper alternative
Coming from China, you may also find these under the brands of Polar Aurora or Aquatop. I don’t really have an explanation for that.
These canister filters are suitable for anyone on a tighter budget.
They provide the best water turnover for the money.
Since they’re manufactured in China you don’t really pay for the name of a famous brand.
They will also come in a full kit.
Ordering one will land you 6 filter pads (2 coarse and 4 medium ones), active carbon, some bio balls, ceramic bio-rings and a 9 Watt UV light for sterilizing. None of the other models mentioned here come with a UV sterilizer.
The SunSun canister also has a priming button. You only need to press it a couple of times, when there’s air inside the unit.
The instructions for the set up seem as if translated straight from the Google Translator (in places they don’t make any sense in English).
This unit is great if you’re absolutely new to filters and you just want to try the idea out without spending a ton of money.
Don’t get me wrong, there are some negatives here, as with all products.
The canister may come off as more fragile. The SunSun canister filters are not as durable as other devices coming from more reputable brands.
You will not need to buy a new unit in the next few months, but there’s no guarantee that they will run for more than 2 years.
Which is still alright, given how they’re crushing the market right now.
The reason for that is their super affordable price tag, coming with the powerful filtration they offer.
They are also easy to install and maintain.
I use one such filter on my larger tank as supportive filtration and I’m pretty happy with it.
Note that the one that’s advertised to offer 525 GPH (HW-304B model) won’t realistically meet that. Still, it will turn over around 300 gallons per hour, which is more than enough for a 55-gallon tank that’s reasonably stocked.
Further down in the article I discuss this in detail.Advantages:
- Comes with a UV sterilizer
- Virtually silent
- Best filtration for the money on the market
- Multiple stages of filtration
- Comes with activated carbon and plenty of filter pads
- Self-priming button
- Not as durable and long-lasting (short warranty)
- Instructions are basically useless (watch this video instead)
- UV sterilizer should not run for a long time
- Plastic impeller (may need replacement in time, but the parts are easy to find as well as cheap)
4. Fluval (X)06 Series External Filter – Extra features
Fluval along with Eheim is the top choice of the experienced freshwater aquarist for canister filtration purposes.
Naturally, they are just a tiny bit pricier, but as you’ll see (and hopefully experience first hand) for a good reason.
The Fluval 06 series offer excellent filtration along with extreme durability.
The units have a really sturdy architecture, manufactured by the best parts on the US market.
The sealing is impervious. The chance of a leak is probably nonexistent. A very long-lasting unit as well.
You can easily avoid the higher price by getting a second-hand device. It will still run like brand new.
The maintenance is a breeze and it’s rarely needed.
The other thing that stands out is the motor.
All of the 06 canister filters have enormous filtration capacity. The GPH advertised is as realistic as it gets. As far as my experience goes, you will enjoy the least GPH reduction after adding livestock and filter media to the equation.
The motor also has sound-dampening features to minimize vibrations during operation. Basically, this filter is quieter when it runs than when it’s off…
Can’t really find a weak spot to point out with these, so if you have the financial opportunity – simply buy this canister filter.
Of course, it all depends on the fish tank setup you’re planning, but I am discussing that further in this article, so make sure you read that.
By the way, Fluval are also famous for their excellent customer service, should you ever need it.Advantages:
- Aquastop valves that ensure no water is spilled during maintenance
- Sound-dampening motor for extra quiet operation
- Will last you years
- Pumps tons of water & is really efficient
- Excellent unit architecture with top-notch parts
- Huge space for filtering media
- Not the easiest to start and prime (watch this video for that)
5. Fluval FX(X) Series Canister Filters – The POWERHOUSE
Namely the FX6. This canister filter is just a full-blown monstrosity.
It has the most pumping capacity on this list (rated for up to 400-gallon aquariums).
This filter is what you get for your large freshwater aquarium that has big, carnivorous fish (or turtles) in it.
The FX canister filters are as good as it gets. Tons of functionality not to be found elsewhere.
The FX6 comes with a Smart Pump technology, which will effectively self-prime the filter every 12 hours.
You also get the typical Aquastop valves, that allow for a care-free maintenance.
The motor itself is an absolute beast and is one of the best on the market right now. With a turnover capacity of over 500 gallons of water, it stands undisputed.
Getting not 5, but 6 stages of filtration are also worth mentioning.
How do you get away with that?
Well, you just put a filter tray within the filter tray.
The unit is big. As in huge.
You will have enough space to stick in whatever filter media is on your mind. The basket-like architecture makes sure the water passes through every filter tray and not around.
I use this filter on my 125-gallon fish tank and I could not be more satisfied. It runs extremely quiet and it easily handles my very messy Oscars (and not only!).
The maintenance is simplistic, though it takes time, because of how the stuff is built.
There is also this additional clog-proofing feature that makes this filter virtually immortal.
You can’t go wrong with getting the FX6, but it comes at a price.
Not something everyone can afford, but if you’re going in the large-aquarium game that is to be expected (and needed).
Here, you’re paying for a high-end canister filter with unique functionalities and top quality service.
Being care-free about your freshwater aquarium filtration for years to come is not exactly inexpensive.
Still, given how much it offers the investment is overwhelmingly worth it. In the long run, you’ll end up saving a fortune.
Don’t just take it from me, ask around your community.Advantages:
- No priming required whatsoever, thanks to the Smart Pump feature
- Pumps water like a champ
- Reduced electricity usage, despite the huge water turnover
- 6 stages of filtration, which no other filter has been able to provide
- Tracks the water flow automatically, adjusts itself when needed
- Self-Protection: will shut off if something inside of it goes wrong, preventing leaks
- As quiet as it’s efficient
- Made to last years
- Tech features that no other canister filter provides
- The nozzle can be turned in multiple directions
- The initial cost of investment (though completely justified)
- Needs considerable space, as the unit is quite large (though if you’re having a stand for your large aquarium it can still fit in)
- Slightly complicated to install if you’re a first-timer to canister filters (click this link for a detailed video walkthrough on that)
6. API FILSTAR XP Series Canister Filters – Pay less for more
Formerly known as “Rena Filstar” these canister filters have maintained a well-known brand name in the freshwater fishkeeping community.
The reason for that is their quality service at a reasonable price.
Compared to other more expensive brands the API FILSTAR will come at a price (sometimes) twice as low for the same filtration power bracket.
They also have all the features of a convenient-to-use device, such as self-priming, anti-airlock system, sound-dampening, and whatnot.
Though they might not be made of sturdy plastic, they are definitely the superior choice when maintaining a larger aquarium on a budget.
I wouldn’t hesitate to use these on a 55 to 75-gallon tanks (I’ve used the XL on a 75 gallon).
The motor is powerful and pumps huge water amounts, as advertised. The XL version has a turnover capacity of 450 GPH, and you won’t find another canister like that for the same price.
This filter comes with its own set of filter media, all of which is brand-patented, because of a unique filtering technology behind them.
These you can stick in 4 separate filter-holding trays that are huge on their own.
This canister filter stands out with its self-priming technology, combined with the quick-disconnect valve. The first is really efficient and the second allows cleaning of the device without the need of re-priming.
I keep saying that priming is very annoying, but here that is completely eliminated.
The disadvantages of this unit are its stiff hoses and the not-so-quiet operation.
It’s still way quieter than a HOB filter, it’s just not virtually silent as other filters that I’m mentioning here.
Though the installation is pretty straight-forward for the canister filter world the hoses can be a pain to connect.
Another thing I consider a disadvantage is the lack of a spray-bar. For a filter that’s as strong, the output pressure can really be something. Without a spray-bar, you’d either need to get one separately or manually drill holes in the outlet. That’s only if you notice your fish getting blown around the tank by the stream.
Not a very big deal, but it’s a small inconvenience. As users, convenience is the second best quality after the performance, that we pay for.Advantages:
- No defined shape of the filter trays, you can easily cut DIY filter floss to use
- Among the top performers for the price
- The best self-priming feature on this list
- No need of re-priming after cleaning, thanks to the quick-disconnect valve
- Durable design of the basket made to last
- Longer than usual hoses, for optimal positioning
- Branded-tech filter pads
- Can be difficult to set up the tubing, unless you know how (check the “Tip” section above)
- Not as quiet as other canister filters but still an overall quiet operation.
- No spray-bar in the kit
- Improper set up of the tubing can result in leaks
Which canister filter will best suit your fish tank size and gallon setup?
Now, it’s easy to summarise short reviews of every piece of canister filter I’ve found to work well. But, for me at least, this kind of information was never useful enough to help me with my purchase decision. I am perfectly aware that it all boils down to one’s freshwater aquarium setup.
Because of this, I want to go the extra mile here.
Below I’ll recommend a particular piece of gear for every possible setup, according to my experience and observations. For optimal recommendations, I am considering fish tank sizes, livestock and aquascape, combined with the pros and cons of particular canister filter units. Here goes my guide on picking a canister filter according to your tank’s size and setup:
Optimum canister filters for a 10-gallon fish tank:
The best filter for a 10-gallon fish tank is, without a doubt, the Eheim 2211 Classic Filter. It’s a canister type of filter that will handle even the most overstocked 10 gals aquarium.
However, with lightly stocked 10-gallon aquariums, a canister filter is not necessary. You will do just fine with a sponge or HOB filter too.
However, a canister filter will provide awesome filtration, while being visually hidden and especially quiet.
A good reason to go for a canister filter here would be if the aquarium stays at your or your children’s bedroom.
I’m assuming you already knew that, if you’re reading this so let’s cut to the chase here.
A small aquarium will get dirtier way faster, because of the confined space. As dangerous ammonia can build up pretty quickly in such a small volume of water, proper filtration is of utmost importance.
Considering your filter media, bioload, and desire to regularly maintain a unit you should (as with all filters) aim for a canister that’s rated for a larger aquarium.
That being said, for a 10-gallon aquarium setup a proper canister filter would be:
The Eheim 2211.
It’s what I can certainly recommend in this situation.
This filter is rated for up to 40 US gallons (click the link above to check the unit on Amazon). Note that the rating is based on an empty unit with no filter pads, running inside a completely empty aquarium with only water in it.
Filter media, how often you clean it, and the amount of livestock all impede the flow rate.
Still, the Eheim 2211 canister is absolutely perfect for a 10 to 20-gallon fish tank. It runs quietly, does not blow your smaller fish and plants around and provides outstanding filtration.
Here are some pieces of advice on that filter, that I must mention:
Don’t use the fine water-polishing pad that comes with the filter. It will surely make your water crystal clear for less than a day, but you’d have to clean it 2 times a week and trust me, that’s a LOT of work.
Double the coarse filter media instead and you should be totally fine.
Another thing to mention here are the instructions for setting it up and priming it. As radical as it might sound, the instructions are complete garbage. Worry not though.
Enter: the Internet.
There are hundreds of people that have that filter already and know how to operate it. Here’s a video of one such person that shows you how to start the unit in a pretty straightforward video that’s just over a minute.
Your third consideration would be the INCOMING flow. In a smaller tank, the fish can be more sensitive to flow. To avoid that you have 2 really simple options:
- Drill small holes in the output pipe to spread the stream of returning water. Making 3-4 holes will be more than enough.
- Adjust the return pipe to point towards the back glass of your tank. This will soften the return flow.
Optimum canister filters for 20-gallon fish tanks:
Before reading this, I appeal that you read the previous paragraphs as most of the same rules apply. When it comes to freshwater canister filters in 20-gallon aquariums the best one is:
For filtering 20 gallons of fish water I’d still go with the Eheim 2211 canister filter. With it, you’ll get a water turnover of about 4 times per hour. This should be more than enough to keep your aquarium debris-free.
Eheim is a big brand in the fishkeeping gear industry for a reason. From what I’ve seen (and owned) it is not uncommon that a filter of theirs would run for 7+ years.
Another quality of the Eheim canister filters that I like is how much space there is for filtering media.
You’ll have plenty of room to house beneficial bacteria in your biological media.
In smaller tanks (10 to 20 gallons) this is very important, especially when you’re adding new fish. Add too many new fish at once and the organic waste produced will surely overwhelm the ammonia-converting bacteria. From there you can get ammonia poisoning which is known to be quite deadly. If not that you will get a nitrite spike, which can also be lethal, especially to freshwater fish.
For all these reasons (along with my bitter experience as a young fishkeeper) I recommend a filter that’s actually rated for up to 40 US gallons. It’s not overkilling, it’s completely justified.
For aquariums that are heavy on livestock (high tech, planted, or with many, many fish) the water turnover will be significantly slowed down. Add the filtration media to that and the flow can be reduced by a third or more.
For a 20-gallon aquarium that’s long, I recommend that you slightly modify your canister filter. As these tanks are notably shorter in height your fish will have less space to float up and down.
In case you’re planning to keep long-finned fish (tetras, bettas, goldfish, angelfish etc.) you should drill a couple of holes in the output pipe. This will reduce the pressure under which the water is being returned to the aquarium. That way the incoming water flow won’t disturb the swimming of these fish. If you have community fish that like to dash back and forth such as Danios, drilling holes won’t be needed as they will enjoy the stream.
For 20-gallon marine tank, I would only recommend a canister filter, if you’re concerned will all three types of filtration: biological, mechanical and chemical. As I mentioned the Eheim 2211 has enough space for filter media and would suffice.
Optimum canister filters for 30 to 40-gallon fish tanks:
The best pick for 30 and 40-gallon freshwater fish tank setups, a sound choice of an aquarium filter would be the Penn Plax Cascade 700 Series (the link points to Amazon).
I own 2 of the higher-rated series and all I can say is that these canister filters are pretty much a gold mine.
They are actually the most common canister filter choice at the moment of writing, and for a reason.
The price is more than reasonable too, as far as these quality filters go.
The Cascade 700 is rated for an aquarium of up to 65 gallons and has a GPH of 185. This means it will turn the water of your 30-gallon tank around 6 times per hour and over 4 times for a 40-gallon.
Such sized aquariums are often heavily planted with lots of community fish in it (trust me you’ll end up like that one day). With this unit and the proper filtration media, you can keep whatever you want in there.
Optimum canister filters for 55-gallon fish tanks:
Have a look at the best filters for a 50 to 55-gallon freshwater aquarium:
- SunSun HW-302. A budget option.
- Eheim 2217 Classic Canister Filter. Long-term investment.
- Fluval 306 External Filter. For an intentionally overstocked 55-gallon tank.
For freshwater aquariums of this size you’d need a stronger canister filter as we’re getting into the higher bracket.
Bigger fish tend to be messier.
I can recommend that you go after either SunSun HW-302 or the Eheim 2217 (click the link to check both on Amazon). They’re both rated high enough to be able to handle a 55-gallon tank perfectly.
What’s the difference you may ask?
The SunSun comes at a lower price and you will get the best filtration for your bucks.
The Eheim is a little bit pricier, but it’s manufactured in Germany – it will run for 5 or more years.
It really depends on your budget.
If you really can’t afford to spend the extra $ then go for the SunSun. By the time for a change comes (still, 2 to 3 years) you’d probably have enough money to get something durable.
However, if right now you have the budget for it – you should absolutely go for the Eheim, as it is way worth it in the long run.
It’s simple – let your pocket decide.
In case you plan on having something very messy such as larger plecos, Oscars, a community of cichlids or some freshwater eels I recommend to step up your game even further, for obvious reasons.
When keeping medium sized fish (or turtles) in there you should think ~260 gallons per hour of water turnover (at the least).
I ran such tank just until recently (I expanded it) and I had a Fluval 306 doing the filtration (visit the link to see the model on Amazon). This canister filter is top-notch and keeps my ammonia where it belongs – at 0.
With such fish in it, I could not compromise with the filtration.
The Fluval 306 is rated for aquariums of up to 75 gallons and has approximately 300 GPH.
Some more experienced fishkeepers may argue that the 406 version will be the better option here.
Frankly, that is true, but only if you can afford it. I am only trying to recommend units that do the best work for their price here.
For this setup, the 406 would make sense if your freshwater tank is heavily overstocked.
Optimum canister filters for a 75-gallon fish tank:
To best filtrate a 75-gallon freshwater aquarium you can try the following canister filters:
- Penn Plax Cascade 1500 Canister Filter. For 75 gals tanks with 80% bioload.
- Fluval 406 External Filter. For a fully stocked aquarium.
- API Filstar XP-XL. For a tank with very heavy bioload.
According to my experience to filter 75 gallons of water in a fish tank you’d need something that can turn the water at least 5 times per hour.
If the tank you have is predatory, containing large fish (or turtles) that are carnivorous and therefore even messier, make that 6 to 7 times.
The Cascade 1500 (click the upper link to view the exact model on Amazon) would be perfect for most setups here. It is rated at 350 GPH which can be enough for a decent filtration.
I use that on my heavily planted 75-gallon aquarium that has small community fish in it. I wouldn’t say it’s overstocked, but I am positive it is close to the top. My readings of ammonia and nitrate are well close to 0, with ammonia being constantly there and nitrites ranging between 0 and 0.2 ppm.
When dealing with a planted tank, however, you’d want enough flow to move around carbon dioxide, without tearing your plants apart. It’s why I chose the 1500 series, and I am (still) pretty happy with my choice.
With larger predatory fish such as Oscars, cichlids or eels things can get dirty.
To be able to actually filtrate the water here you’d need a stronger unit.
The Fluval 406 is rated at a turnover of 385 gallons per hour, and I have to say, that may very well be the real number.
I only have one such tank currently and, despite the messy creatures in it, I achieve crystal clear water.
And let me tell you, with an Oscar that’s 10 inches long the filter you have is probably your most important equipment. If you risk with a weaker filter you may end up killing your monster fish, causing an ammonia poisoning in the water.
By the way, a piece of advice: while on Amazon, look up a used 406 to save some cash. They have an A-to-Z Guarantee Policy to protect their users and ensure quality second-hand stock.
For a 75 gallon tank with a small turtle, or one that is FULLY stocked with cichlid I’d strongly recommend scaling the canister filter up a little.
Price included, but not by much – around $60 when nothing’s on sale.
If that seems like a lot, let me tell you that these $60 can be the difference between wasting $$$ and having to buy a new filter soon after and a healthy year-long filtration.
An appropriate choice here would be the XP-XL canister FILSTAR filter.
Turtles are as dirty as it gets, and if you’ve ever owned one you’d know that.
The Extra-Large version of the FILSTAR is classified as a 295-gallon tank canister filter, but this is not your concern. What we’re looking at here is the GPH, which is 450, as advertised. Enough to handle a 75-gallon turtle-inhabited tank.
Including all the filter media and whatnot, you’d get a realistic turnover of around 380 to 400 gallons per hour.
It also has 4 filter media trays, for you to stock with whatever pads you desire. This will suffice for even the messiest turtle and you won’t end up tearing your tank down, because of stagnant water issues.
For a 75-gallon saltwater aquarium, I’d go with the Fluval 406. It will perform pretty well, no matter the purpose – biological, mechanical or chemical filtration. Just remember to really clean it often. For a marine system larger than 75 gallons the canister filter would be only an additional filtration and using a sump as your main one is highly recommended.
Optimum canister filters for a 90-gallon & a 100-gallon fish tank:
The best choices for a canister filter on a 90 to 100-gallon aquarium are:
- Fluval FX6 Canister Filter. If you want a single unit choice.
- The SunSun HW304B. Get 2 of these as a budget alternative.
We’re really getting into to high bracket of freshwater canister filtration here.
I’m guessing that if you plan to have a 90 to 100-gallon freshwater fish tank you’ll absolutely stock it with medium to large-sized fish. The livestock defines what canister filter you should buy, really.
If it’s that rare case where you just want a lightly-to-not planted 90-gallon tank with hundreds of small community fish in it, then, surely, a Fluval 406 will do the job. It’s a high-quality canister filter, that provides strong flowrate of up to 385 GPH. The filter pad trays are not the largest out there, but they will be more than enough for such a setup.
However, this is often not the case. For a tank that’s heavily stocked with cichlids (who are super waste producers), or another medium to large carnivorous fish you’d absolutely need a powerful filtration.
Enter: Fluval FX6 (with a link above, to check this exact model on Amazon).
Really an astonishing canister filter with monstrous water turnover capacity.
It will circulate the water in your tank 5 to 6 times, depending on the filter media.
Fluvals are reliable and work as described.
They’re quiet, yet super powerful. I don’t really see any other filter suitable for a setup like this.
I don’t have 90-gallon, nor 100-gallon tanks at the moment, but I run an FX6 on my predatory 125 gals (in combination with another filter, which I will mention below).
I’m sure you did notice the price, though.
I can mumble all day how the numbers are justified, but I won’t bore you with that (up in the article I did a review if you want to check that out).
Essentially you get what you pay for. And this investment will probably last you no less than 5 years from my experience.
This filter can handle the waste of pretty much anyone – turtles, large fish or both.
It has enormous space for filtration media, as well.
It’s really the best canister filter for larger aquariums on the market, right now.
In fact, it’s so powerful that occasionally it may suck up a baby fish or five. If you have that make sure you secure the intake pipe with a barrier of some sort. Or simply move them to a breeding tank.
I’m aware of how that sounds, but it’s not as bad as you may think.
The SunSun HW304B (link to Amazon above, by the way) claims to turn over 500 gallons of water per hour. In my experience, this is not the truth, but it still realistically reaches over 300.
Now, look at its price.
That’s right, you can get two of these canister filters for less than a single FX6.
For a tighter budget, these are absolutely killing the competition.
They do move around plenty of water and have 4 trays for filtration media.
With 2 of these, you will provide crystal clear water in a well-stocked 90-gallon aquarium. The SunSun HW304B is the go-to choice for many frugal aquarists with larger tanks.
However, I think it’s important to mention that these filters won’t last you for 5 years, and if they do, there may be some repairs along the way.
Also, they come with a UV sterilizer, which I don’t recommend turning on for more than a couple of hours on the weekend. The sterilizer will eat through the plastic if it stays on for longer than that.
Overall, they are a pretty good choice for a tank of this size if you don’t currently have more money. If you do – go for the rock-solid FX6.
If you don’t – buy two of the SunSuns and be done with it, until you can afford something better.
A SunSun will last you for at least a year and a half with proper maintenance.
Optimum canister filters for 125 gallon or larger fish tanks:
In a 125-gallon fish tank, the filter is the most important piece of gear along with the lighting fixtures. Tho best filtrate a 125-gallon aquarium you can choose among these canister filters:
- Fluval FX6 Canister Filter. Use as a primary filtration unit.
- Penn Plax Cascade 1500 Series. Use as a secondary filtration.
There’s no easy way around this.
To keep such large freshwater tank realistically clean you’d need 2 separate canister filter units. The combined GPH of both should revolve around 1000 for a 125-gallon aquarium. For larger tanks – aim for a water turnover of 7 to 8 times, because filter media and stocking will hinder the advertised flow rate of your units.
And now the big question – what canister filter combo should you use in a 125-gallon fish tank?
My success has been with combining one quality filter and a cheaper one, to make up for the additional filtration.
Of course, that strongly depends on your livestock. If you plan on having a large, heavily planted tank with 3 or 4 cichlids in it a single FX6 unit may suffice.
However, my guess is that you would like to have at least 3 medium to large sized fish in such one tank.
Or stock it with all the cichlids you could find. Or have some mean turtle(s) that will double in size in the next couple of months. Or, perhaps, a silly 30″ long freshwater eel.
All of which produce copious amounts of waste and need killer filtration to thrive.
On my 125-gallon tank that’s housing my huge Oscars, I run a Fluval FX6 + a Penn Plax Cascade 1500 Canister Filter (linking you to both on Amazon in the bullet section above).
My water is as transparent as air and my ammonia and nitrite readings are solid zeroes.
If you’re lower on the budget you can replace the Cascade 1500 with a SunSun HW304B, which is half the price, but still provides strong filtration.
The Cascade will be more durable, though they have the appearance of a cheaper filter at first sight.
Investing in a high-end filter will save you tons of anxiety in the long run.
It’s how you should view it – as an investment.
It’s the reason why I got the FX6 and so should you WHEN you can afford it.
If you have the pocket for it, this canister filter is a no-brainer. The motor of the Fluval is among the best on the market right now. They are also long-lasting and the chance of breaking is insignificant.
Though a sole unit like this won’t be enough for a 125-gallon tank with such setup, it still does a great portion of the filtration for me.
In my opinion, the FX6 is a must, but you can get flexible with your second unit.
If you want to go full Fluval you can use a 406 as your secondary filtration.
If you want to approach the matter in a frugal way you can buy a used unit on Amazon and save at least half of the price. If you choose to walk that path, know that Amazon has a solid protection policy to ensure you get quality second-hand equipment.
As for a canister filter for a marine 125+ gallon tank… I don’t think they will outperform a well-built sump. Adding a Fluval FX6 as additional mechanical filtration could be fine, but I deem it an overkill, as sumps will work best for these setups.
How to select the best canister filter for a tank that has turtles in it?
I mention turtles a couple of times above, but the truth is that things will differ with such a setup:
For a turtle aquarium, you’d best have a really strong canister filter. One that would turn the water at least 8 times per hour, according to the 8x Rule.
Don’t know why? Don’t have the time to research for yourself? I made a whole separate guide on turtle-suitable tank filters because the differences in the requirements for the equipment demands it. There, I give extra pointers and discuss all the possibilities for a turtle setup (with or without basking areas, etc.).
Making a decision can be tough unless you have a more experienced fellow point you in the right direction.
All of the aforementioned devices have their pros and cons.
The smart approach here is to make the most sense of the pros while overcoming the cons.
The best and most efficient canister filter exists and it is different for every freshwater setup.
I hope this guide was helpful (it took me quite some time to put it together).
which aquarium filter did you pick?
Tell me in the comments so we can discuss it further.