Stephen is an owner of several aquarium supplies shops in New York. Like no one else, he knows how to pick the perfect fish tank or any aquarium accessory from pump to artificial decorative plants.
Last updated: April 04, 2022
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For hang-on back filters, their setup typically involves hanging them on the back of the fish tank, often with minimal assembly needed beforehand. Given this ease of use, it’s no surprise they’re as popular as they are.
That said, some hang-on back filters might not be effective at cleaning your aquarium. As such, we’ve reviewed, picked, and listed below the hang-on filters with the right capacity, flow rate, and filtration stages to leave the fish tank water crystal clear and free of impurities. As such, if you’re looking for the best hang-on back filter for your aquarium, this list should help you out.
Other features: patented Bio-Wheel technology, two-piece vented cover
The MarineLand Penguin Bio-Wheel Power hang-on filter is a 50–75-gallon capacity device that incorporates three filtration stages in its design. It’s also designed with bio-wheel technology, which offers optimal conditions for the growth of bacteria. This enhances its biological filtration performance. The chemical and biological filtration media are also included, although you might have to replace them at a later date.
One of the filter’s differentiating factors is the larger surface area for bacteria provided by the patented bio-wheel. This allows it to neutralize ammonia and nitrites as soon as they come into contact with the device. As such, if you want better biological filtration, you should consider purchasing this hang-on filter.
What are its best features?
For a 50–75-gallon device, we noticed it has an impressive flow rate which translates into faster cleaning for your aquarium. Also, as mentioned above, it offers optimal conditions for bacteria to breed and grow, which improves its biological filtration performance. This is in addition to having a larger surface area for the bacteria to populate. In our opinion, this filter is also a cinch to put together.
What could be improved?
While the fast flow rate is ideal for faster cleaning, it can be a problem for small fish that can’t swim in fast-moving water. Additionally, it’s a bulky device, not to mention it’s slightly heavier than most of the competition. As such, for some, it will prove an eyesore on their aquariums. Also, if you let the water drop to a certain level, it becomes noisy.
Other features: Bio-Falls Quad-Filtration system, adjustable flow knob
If you’re looking for the best hang-on back filter for a 55 gal tank or larger, the Penn-Plax CPF5 Cascade Hang-on Aquarium Filter definitely qualifies. In fact, it can handle aquariums with up to a 100-gallon capacity. It’s designed to work with disposable double-sided cartridges that combine poly-fiber floss and activated carbon for mechanical and chemical filtration.
A key design feature of this filter that sets it apart from others is the separate bio-sponge cartridge that works independently from the mechanical and chemical media. As such, users won’t have to worry about the beneficial bacteria whenever they change the other filter media. It also means that changing filter media will be a lot easier.
What are our favorite features?
The Penn-Plax CPF5 Cascade Hang-on Aquarium Filter has an impressive capacity, and if you have a large aquarium, it could be just what you need. Additionally, we liked the adjustable flow knob, and it may come in handy during feeding times or a water change. The design of the bio-sponge cartridge also makes the filter more convenient to use.
What could be better?
Replacement filters may not be as easy to find in your local stores. Also, if you use it in a fish tank with plants, the intake clogs pretty easily. Additionally, it’s challenging to clean once this happens. We also noticed it gets louder with time, and it can be a problem for people who don’t like the noise. Lastly, the flow rate is relatively slow for a filter designed to work with 100-gallon fish tanks.
As for the Tetra Whisper EX70 Silent Multi-Stage Power Filter, it works with somewhat similar tank sizes to the editor’s choice, and the flow rate is almost the same. Additionally, it incorporates an extra filtration stage, which can leave the water in your fish tank clearer and cleaner. Lastly, the filter is built with convenience in mind as the filter cartridges are easy to remove and change whenever necessary.
This device is for users who want an easier time changing filter cartridges while at the same time ensuring they don’t have to do much clean-up afterward. It’s also for medium to large fish tanks, given the 45-70 gal capacity. Lastly, it’s unique in that it adds an extra filtration stage to ensure a cleaner environment for your fish.
What are its best features?
Notably, installing the filter is a simple three-step process and thus should be easy to hack for most people. Additionally, the power and flow rate of the device ensures there’s enough aeration in the fish tank while removing impurities. Also, the device maintains relatively quiet operation even with all the extra power.
What could be improved?
We noticed loud splashing sounds from the setup, especially when the water levels in the tank were low. This makes it necessary to fill your water tank almost to the brim, making it hard to keep semi-aquatic animals like turtles in the tank. The extra power also makes it unsuitable for smaller fish.
Another hang-on back filter to consider is the AZOO Mignon Filter 60, especially if you have a small fish tank. After all, it can only work with 3.5-gallon fish tanks or smaller. As such, the 15 GPH flow rate is more than enough for such a small fish tank. Also, it incorporates biological, chemical, and biological filtration in its design.
If you’re looking for a small hang-on back filter to cater to the needs of a small aquarium, then the AZOO Mignon Filter 60 is an excellent pick. Next, the flow rate is a key differentiating factor as it allows for faster cleaning of your fish tank. The warranty is also impressive for the money, and it’s ideal for users who prefer quiet operation.
What makes it special?
In our opinion, this little device features quite an efficient design. It comes with a small black knob that stabilizes the device during use. Consequently, in addition to being efficient, it’s also quiet. Additionally, the fact that the pump comes included is quite impressive for such an inexpensive filter. Lastly, like the Penn-Plax CPF5 Cascade Hang-on Aquarium Filter, it comes with a flow rate control knob.
What cons did we find?
The mechanical filtration media provided with the initial purchase isn’t the best quality, and you might have to upgrade it. Also, even when you change the flow rate to the lowest setting, the current is still strong enough to be a problem for smaller fish such as bettas. Lastly, the install instructions may not be much help.
The AquaClear A610/50 Fish Tank Filter is one machine that can help you save on costs thanks to the energy-efficient pump included. Besides that, it works well with fish tanks in the 20-50 gal size range. Like most other filters listed, it offers three filtration stages to get rid of contaminants in the water. Also worth noting is the lifetime warranty.
If your fish tank can hold between 20 and 50 gallons of water, this device is perfectly suited for cleaning it up. It also provides more contact between the water and the filtration media for more effective cleaning. Lastly, it differentiates itself from other hang-on back filters with similar capabilities by coming with a lifetime warranty.
What are its best features?
Not many hang-on back filters for 20-gallon tanks or larger offer a lifetime warranty during purchase, making this offering unique. Additionally, since there is more contact between the water and the filtration media, your tank is bound to end up with cleaner water. Another positive is how easily you can set up the filter.
What could be improved?
We noticed that if the power goes out, water drains out of the filter reasonably quickly, and you have to refill it manually. As such, you can’t leave the filter unsupervised. Lastly, the filter media basket will float on the water, which will sometimes cause it to push up on the device's lid. Ultimately this often leads to spills.
Other features: self-priming, LED indicator light, lifetime warranty
One of the best hang-on back power filters for 45 gal fish tanks or smaller is the Aqueon QuietFlow, thanks to the inclusion of extra technology that makes it easier to use. One example is the self-priming feature that eliminates air bubbles from the tubing, therefore, protecting the motor. Another example is the LED indicator light that tells you exactly when the filter media needs changing.
This filter is designed for users who are prone to forgetting when they should clean the mechanical filtration media. The device monitors the water levels, can tell if the filter is clogged. As such, it can notify you via the LED indicator light when it’s time to change the filter. Another differentiator is that it starts automatically after a power outage or clean-up session.
What makes it special?
One of the biggest positives for the Aqueon QuietFlow LED PRO Aquarium Power Filter is the ease of use as a byproduct of the few automation features included in its design. This consists of the automatic start after clean-up or power outages and the self-priming feature. Furthermore, there’s the lifetime warranty that comes standard with the purchase.
What cons did we find?
In our opinion, the Aqueon QuietFlow LED PRO Aquarium Power Filter is relatively loud during use and, therefore, may affect where you decide to position the fish tank. Additionally, there’s no way to adjust the flow rate to match different scenarios, such as feeding times for the fish. Also, we noticed the single cartridge included clogs up fairly fast.
The TARARIUM A-HBL701-Filter Aquarium Power Filter is one of the best options for cleaning the surface of the water in your fish tank. It comes fitted with a surface skimmer that will rise or go down with the water levels in the tank. Also, with a 40 dB maximum sound output, it’s safe to say that the machine is pretty quiet.
This filter is for users who want more effective clean-up of the water surface. It can even remove oil slicks from the surface of the water. Of course, the feature that makes this possible is the surface skimmer, which can rise and go down with the changes in the water level.
What stands out?
Setting up this hang-on back filter is a seven-step process that should be workable and easy to do for most people. Next, we liked the inclusion of a sponge on the water intake to protect your shrimp and fish from being sucked into the filter. Another positive is the skimmer we mentioned above, as it’s capable of cleaning oil slicks which is a feature that not many other filters offer.
What cons did we manage to find?
If you’re going to use it on a 55 gal fish tank, the flow rate isn’t anything impressive, and the resulting clean-up process may be a little sluggish. Also, the surface skimmer can be blocked by solid matter if you’re not careful. As such, you may need to add something like a piece of cloth or a plastic mesh to keep it functional.
Similar to the AZOO Mignon Filter 60, the EA Performance Hang-On The Back Power Filter is meant to work with small aquariums and small fish. As such, the flow rate is slow enough not to affect the fish. It comes fully assembled, and the only things you have to do are place it in the fish tank and plug it in. Additionally, it only supports mechanical and biological filtration, so you might have to look elsewhere for chemical filtration.
This filter is excellent if you have a small fish tank with similarly small fish species such as betta and other nano fish. It’s also great if you’re looking to avoid a long and complicated setup process, given that it comes assembled and ready to plug and play.
What are its best features?
In our opinion, this filter caters well to the intended market by having a low flow rate that won’t be detrimental to the kind of fish you find in 4 gal aquariums. Additionally, installing this filter is a simple process that involves putting it in the fish tank and plugging it in. There’s no assembly needed.
What could be improved?
One major flaw in this filter's design is the lack of support for the chemical filter media. As such, you may have to introduce it directly into the fish tank. This also means it will be challenging to position it where there is a constant flow of water, and this can hinder its effectiveness.
Other features: easy installation and clean, quiet operation
If set up the right way, the BNYEE Aquarium Fish Tank Hang Filter offers four stages of filtration. However, you’ll have to budget for the media as an extra purchase which also gives you the freedom to choose the type of media you want. This, of course, makes installation fairly straightforward, and what’s more, the filter doesn’t make much noise as it does its job.
If you want a filter that allows you full control over the filter media you use, the BNYEE Aquarium Fish Tank Hang Filter is an excellent device. What’s more, it differentiates itself by allowing users to include up to four stages of filtration. Lastly, with the snap design, taking out the media and cleaning them should be a piece of cake.
What stands out?
One of the positive inclusions in the device is the ceramic axis that makes up part of the motor. The axis is wear-resistant, and the engine is quiet in operation. Another pro is the freedom to choose whatever filter media you want. You could even interchange the positioning of the chemical and mechanical filters depending on water quality.
What cons did we manage to find?
While the device allows for more contact between the water and the filter media, there’s no denying that it’s pretty bulky for a 15 – 45 gal machine. Also, it’s relatively expensive, and buying the media will only increase the costs as you have to buy four of them at once.
Other features: adjustable water flow and tube heights, effective surface skimming
The TechnologyMatter Ultra-Quiet Aquarium Filter works well whether you’re you’re looking for an excellent hang-on back filter for freshwater or saltwater. It’s a 1.1 lbs device that you should only buy if your fish tank is 20 gal or smaller. Once installed, it will offer a 50 GPH flow rate and efficient tank clean-up. That said, you can also adjust the flow rate whenever you want. Also notable is that it doesn’t use the typical filtration media used in other hang-on back filters.
Like the TARARIUM A-HBL701-Filter Aquarium Power, this TechnologyMatter Ultra-Quiet Aquarium Filter allows for more efficient cleaning of the water surface. As such, if you constantly have solid materials on the surface of your tank water, you should consider owning this device. This is thanks to the adjustable tube heights in the device.
What do we love it for?
We noticed that this filter is also designed with a buckle at the bottom of the motor. This helps stabilize it as it works, reducing the noise levels significantly. Another positive is that you don’t have to manually adjust the tube height as it’s designed to make those changes automatically.
What were we disappointed with?
While it offers automatically adjustable tube heights, there’s no easy way to know if this feature is working or not. As such, if it starts to malfunction, you may not notice until the filter’s efficiency has been dramatically reduced. Also, in our opinion, the flow rate is nothing special for a 50 gal tank and may slow clean-up progress.
Things to Consider
It’s worth noting that buying the wrong hang-on back filter can negatively affect your fish’s health. As such, even if you’re a newbie, you don’t have any margins for error which is why we’ve come up with this buying guide. You can use it to determine which of the best hang-on back filters listed above is worth your money.
Benefits of HOB Filters
The main benefits of HOB filters are easy setup, maintenance and afffordability
As mentioned above, hang-on back filters are easier to set up since they only need to be hung on the rear wall of the aquarium. This can also make maintenance easy as the filter media are always within reach. You just have to turn off the device and lift it out of the water.
Another benefit is the filter’s affordability. They typically cost $50 or less, which means most people won’t struggle to buy or replace them. Also, their design allows them to be hidden behind the back of the fish tank, making for a more aesthetically pleasing setup. Lastly, they’re just as effective at aerating the water as other filters, thanks to the free flow of water that agitates the water surface in the aquarium.
How to Pick the Best Hang on Back Filter
For a more concrete idea of how to pick the best hang-on back filter, here’s a summary of all the areas you should pay attention to as you vet each device.
Size and Capacity
A keener look at all the HOB filters listed above shows their sizes vary, and so does their capacity. Notably, aquarium sizes also vary, with some only having a 3 gal capacity while others can hold more than 70 gallons of water. This is one reason to look at the capacity. For instance, you can’t expect the EA Performance Hang-On The Back Power Filter to clean the water in a 45 gal tank as its capacity is limited to 4 gallons.
You also want to note the size of the filter in relation to the size of the fish tank. After all, some filters may be too small or too large for your aquarium.
The flow rate is another area that determines the usability of the device. Consequently, the flow rate you pick should be conducive for your fish population and size. For instance, the 340 GPH flow rate of the MarineLand Penguin Bio-Wheel Power Filter will be surplus to requirements if you only keep nano fish.
However, if the fish are bigger, they shouldn’t have any problems swimming in the currents caused by the machine. Additionally, the gold standard is that the filter should be able to cycle through all the water in the tank three or four times in an hour. As such, for the best hang-on back filter for 10-gallon water tanks, you should only pick devices with a 30 to 40 GPH flow rate or higher.
In some cases, the adjustability of the flow rate is also vital as you may need to lower or raise it while handling some tank maintenance or feeding the fish.
Another element of the filter’s usability is the filtration stages included. Ideally, the water should pass through mechanical, chemical, and biological filtration stages. Some hang-on back filters may even add an extra filtration layer, depending on their size and design.
With more filtration stages, you get cleaner water. However, it can also mean the device is slow. Additionally, you’ll need to buy more media every time a replacement is necessary, which means higher maintenance costs.
According to Science Direct
Trusted SourceBiofilter - an overview | ScienceDirect TopicsBiofilters are also the most common method for removing VOCs and odorous compounds from air streams.
, the biological filter contains two groups of bacteria, i.e., those that convert the ammonia in the fish tank to nitrites and those that oxidize the resulting product to nitrates.
By doing so, the filter can neutralize the harmful ammonia. Since ammonia is excreted by the fish, there’s no way to get rid of it completely, and thus you always have to ensure that there’s a biological filter and that it’s always in tip-top shape.
Chemical filtration works by adsorption, and according to Thought Co
Trusted SourceWhat Does Adsorption Mean in Chemistry?Discover what adsorption means in the world of chemists. Learn the difference between adsorption and absorption. See examples of adsorbents.
, it’s the process by which chemical species adhere to the surface of particles. As such, it’s used to change the chemical makeup of the fish tank contents. Mechanical filtration just gets rid of all the solids in the water. As such, each filtration stage has a role to play, so it may be necessary to have all of them, although in some cases, you can skip the chemical filter.
Priming is a necessary prerequisite to using your hang-on back filter. This is because it eliminates air bubbles in the tubing and protects the motor in the filter from damage. Consequently, most manufacturers recommend priming the filter with water before turning it on. However, some options like the Aqueon QuietFlow LED PRO Aquarium Power Filter come with an automatic self-priming feature and therefore reduce your workload whenever you’re setting up the device.
Ideally, the durability of the hang-on back filter should also be top-notch to ensure that it lasts a while after purchase and through rigorous use. You can even look at specific components to determine the device’s overall durability. With the BNYEE Aquarium Fish Tank Hang Filter, for instance, you get a ceramic axis that’s less prone to wear and tear.
Ease of Maintenance
Also, if you pick a HOB filter that’s easier to maintain, keeping your fish safe will be so much easier.
HOB filters require cleaning every few weeks
Other HOB filter features may also come in handy while using the device. Examples include the LED light indicating when you should change the filter media, surface skimmers, components that stabilize the device, as well as keep the noise levels low, and much more.
How to Set Up a Hang on Back Filter
Ultimately some of the steps for setting up your hang-on back filter are unique to each device. That said, there are some common steps shared among most devices. The first is adding the filtration media. Notably, some devices come with instructions on setting up the media. There may even be directions on individual filter baskets showing where each media should go.
Next, you need to position the filter at the back of the tank. There may be a slot on your tank’s lid for the filter, but if it’s not present, you should place the device where it’s the least visible. Remember to prime the device if it doesn’t have a self-priming feature by filling it with water. Lastly, you plug in the device and turn it on.
How to Maintain HOB Filters
Maintaining your HOB filter typically involves unclogging your filter media and replacing it when necessary. Of course, over time, the mechanical filter will fill up with solid materials collected from the fish tank. This makes it tricky for water to be passed through the filter by the pump as there are no spaces for the water to flow through.
Consequently, you’ll have to take the mechanical filter out for regular cleaning. This process should also coincide with the water change schedule for the tank. That way, you can use water that you drain from the tank to rinse the media.
Remember, the bacteria that form the biological filtration media also live on the mechanical filter. As such, if you rinse it with regular tap water, you may kill the microorganisms. However, if you clean with the drained aquarium water, you can keep the bacteria alive.
Of course, you’re going to have to replace the water you drained from the fish tank. Remember to neutralize chlorine and ammonia in regular tap water by using a water conditioner before introducing it to the tank. This makes it safe for the fish.
If the mechanical media falls apart, replace it with new media. You can do this after removing the old media and dipping it into the drained tank water. That said, you shouldn’t discard the old media. Instead, you should reintroduce it to the fish tank or filter so the bacteria can move into the new media. Of course, you can discard it once this is done.
For chemical filtration media, you just have to replace it according to the manufacturer’s instructions. If the manufacturer says you should replace it monthly or once every two weeks, depending on the size of the tank, then you should do just that. After all, unlike mechanical filters, it’s impossible to tell whether or not the media is full just by looking at it.
Often the noise made by the HOB filter results from water splashing onto the water surface in the tank as it exits the filter. As such, lowering the outlet of the filter, so it doesn’t splash as much water can help reduce the noise. That said, the splashing is also necessary for the aeration of the fish tank, so don’t lower it too much.
Ideally, planted aquariums need a horizontal flow of water. As such, given that water from the HOB filter flows downwards, it may affect the plants negatively and hence is less than ideal.
Additionally, plants generally breathe in CO2. However, the agitation of the water surface in the tank causes the release of the gas, and thus the plants will have less air to breathe. Consequently, if you have plants in your aquarium, it may be best to look for alternatives.
Generally, it’s not a problem to use a HOB filter in a shrimp tank. However, these aquatic creatures are so small that they may be sucked into the filter’s intake. As such, it’s best to block this pathway by using cloth or sponge pre-filters to protect the shrimps.
The Penn-Plax CPF5 also provides an extra biological filter media that you won’t have to clean as often as the mechanical filter. This makes filter and pond maintenance so much easier. The Tetra Whisper EX70 also qualifies as one of the best hang-on back filters in the market, thanks to the extra filtration layer and the impressive flow rate. In fact, the similarities between this model and the editor’s choice guarantee it a stop high up on the list.
Biofilter - an overview | ScienceDirect Topics
Biofilters are also the most common method for removing VOCs and odorous compounds from air streams.