Best HOB Filters for Your Aquarium in 2021 – Hang on Back Models

Updated on by Patrice Alsteen | Affiliate links may be present.

Hang on Back filters have come a long way from the clunky, noisy things of the past to today’s silent and efficient aquarium cleaners. Nowadays, they are among the best options for cleaning home aquariums.

Most of today’s HOB filters combine high filtration capacity, quality filtration media, and simple maintenance. They also come in many different sizes and power classes to suit the needs of different aquarium owners.

My Favorite HOB Filters for Home Aquariums

Choosing the right filter depends on many factors and can be somewhat tricky at times. Read on for my list of the best HOB filters and an in-depth guide on how to choose the right one.

The Fluval C4 Power Filter is designed for 40-70-gallon tanks. It comes in a compact body and fully assembled. Simple and easy setup is one of its strongest points. This filter is a bit on the noisier side, though it makes up for it with a more-than-decent filtration capacity rated at 264 gallons per hour.

This compact filter is one of the more affordable options in its class. It comes with all three types of filtration media and activated carbon. It also has a drip tray pad to prevent water from splashing when returning to the tank.

  • Good filtration capacity
  • Includes a drip tray pad
  • Lightweight and powerful
  • Works well with a wide range of tanks
  • Somewhat noisy

The most important thing to consider when buying a HOB filter is the capacity of your tank. If you have a 20-50 gallon tank, then the AquaClear 50 Power Filter might be an interesting option to consider. This AquaClear comes with great filtration capacity, low operation noise, and an outstanding selection of filtration media, especially in the biological filtration section.

On the other hand, it is a bit of a high-maintenance filter, as it requires biweekly cleaning. However, it makes up for that with its simple and easy setup and cleaning process.

  • Great filtration ability for its class
  • Silent and smooth operation
  • High quality filter media
  • Easy installation
  • High maintenance

This mighty HOB filter is made for 50-80-gallon tanks. It offers a great filtration capacity at 400 gallons per hour. The Emperor 400B (B for black) is a large and robust filter that’s built to last. Reliability and easy handling are also among its stronger points.

The filter supports all three filtration media types – mechanical, chemical, and biological – though you will have to buy them separately. Also, it is among the noisier units. Depending on the size of the tank and how densely it is populated, you’ll need to clean this filter every two to four weeks.

  • Excellent filtration rate of 400 gph
  • Robust and sturdy construction
  • Low maintenance
  • Easy cleaning and installation
  • On the noisy side

The small and compact Marina S10 Power Filter sports a neat design. It is made for small home aquariums of no larger than 10 gallons. Anything bigger is out of its league. The filter has a simple setup and doesn’t need priming. It is submerged and uses only mechanical and biological filters.

Thanks to the fact that it works submerged, it is a great space saver if you live in a small apartment. The Marina S10 has good filtration capacity for its class, being able to clean a tank rather quickly. The low price is also among its strong points.

  • Very affordable
  • Self-priming
  • Low maintenance
  • Easy setup and cleaning
  • Not suitable for tanks over 10 gallons

The Aqueon QuietFlow 75 LED Pro is the biggest model in the QuietFlow series and it’s made for big tanks and serious workloads. It is designed for aquariums of up to 75 gallons and it filters at 400 gallons per hour. Also, it has an LED indicator to inform you when the filter cartridge needs to be replaced.

This filter comes with a submerged water pump which helps reduce noise. Also, it doesn’t need priming before the start, as it is self-priming. All three types of filter media are supported.

  • Great filtration capacity
  • Sturdy and resilient construction
  • LED indicator for cartridge replacement
  • Simple and easy maintenance
  • Big and heavy

MarineLand’s Penguin series is made up of several models, of which the 350 is the biggest and the most powerful. The flow rate of 350 gallons per hour is enough for tanks of up to 70 gallons in capacity.

The Penguin 350 Power Filter offers three levels of filtration – mechanical, chemical, and biological. It comes with an activated carbon filter and a bio-wheel. On the downside, it does require a bit of work to install and set up.

  • High quality filter
  • High filtration rate
  • Offers mechanical, chemical, and biological filtration
  • Low maintenance
    • Needs a bit of work to install and set up

This robust filter features a great combination of affordability and high cleaning capacity. It is made for big aquariums in the 55-110 gallons range. It can work in both salt and freshwater setups. Officially, the flow rate is rated at 250 gallons per hour. The self-priming pump and self-cleaning impeller are among its premier features.

The only noteworthy downside of this mighty tank filter is its somewhat noisy operation. However, it more than compensates for it with its adjustable flow, maintenance monitor, and simple setup. Also, it supports all three filtration media types.

  • Can work with up to 110-gallon tanks
  • Self-cleaning impeller
  • Maintenance monitor
  • Sturdy and reliable construction
  • Self-priming pump
  • Noisy

How Do HOB Filters Work?

HOB filters are straightforward systems that work in a rather simple way. They suck water in through the intake tube which then releases it into the canister. The filter then moves the water through the installed filtration media. Most commonly, a mechanical filter is used in the first stage. Chemical and biological stages are in second and third, respectively. After the cleaning process is done, the water is returned back into the aquarium.

If the intake tube is too close to the surface, your HOB filter might only get to a small percentage of water near the top. This would leave the water elsewhere in the tank dirty and unhealthy for your fish.

Filtration Media

One of the first things that you should consider when buying a HOB filter for your aquarium is the type of filtration media. Some models support only one, while others might combine two or more. The three main media types are mechanical, chemical, and biological.

Ideally, HOB filters should have all three types of media. However, you should inspect the quality of the included media before making your final decision. It is better to invest in a filter with one or two media than a filter which has all three but does a poor job. Here’s a word or two on each type of filtration media.

Mechanical Media

Mechanical media usually make up the first line of defense against the dirt in your aquarium. They are primarily in charge of removing large pieces of debris, such as pieces of uneaten food, detritus, pieces of leaves, and other stuff.

Most commonly, a HOB filter uses a set of ceramic rings or a thick mesh as the mechanical filtration media. There are also other types of mechanical media.

Chemical Media

Chemical media are there to remove chemical impurities from the water. Their task is primarily to remove ammonia and other harmful chemicals invisible to the naked eye. HOB filters may come with various types of chemical media, though zeolite and activated carbon (usually in the form of carbon bags) are the most common options nowadays.

Biological Media

Biological media provide the tank with a place to grow healthy bacteria. They should be made of porous materials and have large surface areas. They most commonly come in the form of bio rings, though ceramic rings can work as well.

The healthy bacteria feed on the nitrate that’s found in the water, thus preventing it from poisoning the plants and the fish in your tank.

How to Clean a HOB Filter

All HOB filters retain some dirt and debris as they work and they all need periodic cleaning. Depending on the quality and efficiency of the installed parts, as well as the size of the tank they’re paired with, HOB filters should be cleaned every two to four weeks.

For example, if you have a big filter and a not-so-crowded tank, it may be ok to clean it once a month. On the other hand, if your tank is large and densely populated, it is recommended to clean the filter every two weeks. While the cleaning process might vary slightly from model to model, here are the basic steps which apply to pretty much all HOB filters.

  1. First, you should unplug the filter from the power source.
  2. Then, remove the lid on top of the filter.
  3. Take the filter basket out of the filter’s housing. In the basket, you will find the mechanical, chemical, and biological filtration media. These might include, but are not limited to, meshes, sponges, carbon bags, beads, and others.
  4. Proceed with cleaning the beads. Generally, you should fill a bucket with the old water from your aquarium and clean the beads with it. You should avoid tap water here, as it will remove the beneficial bacteria from the beads.
  5. After that, use a cleaning brush to remove the algae from the inside of the intake stem. Clean the intake tube in the same way as well. Cleaning tubes will maximize water flow rate and thus the filter’s efficiency.
  6. The next step is to remove the motor of the filter. Again, use a brush to clean the impeller. If necessary, replace it and add some lubricant to reseal the motor’s gasket.
  7. When the cleaning is done, you should reassemble the filter and place it back on the back of the tank. Finally, fill the cartridges (unless you have a self-priming filter) with water and plug the filter back in.

How to Reduce the Noise

In the past, HOB filters had a bad reputation due to their excessive noise. Nowadays, HOB filters generally run smooth and quiet. However, if your HOB filter gets noisy, there are a few things you can do to fix it.

The most usual cause of noise is the sound of water splashing back into the tank. To remedy this, raise the water level to a sufficient height. Alternatively, you can add filter floss to slow down the water and prevent it from splashing on the surface.

Sometimes, your HOB filter might experience difficulties taking water into the canister. If that’s the case, check if all the tubes are tight and in place. Also, make sure the water level is high enough.

Finally, if the noise is coming from the motor compartment, it might mean that the engine is dirty and in need of cleaning. Take the filter apart and remove the debris. Once you’re done with the cleaning, put the filter together and plug it back in.


Hang on back filters are a handy and affordable alternative to the more complicated in-tank filters. They are compact in size and offer respectable performance and low operation noise. HOB is the way to go if you have small and medium-sized tanks. However, for the really big tanks, it is still recommended to go with a more powerful filtration system.

That being said, you should pick a HOB filter which suits the needs of your tank. Also, consider the types and the quality of the filtration media that it comes with, how easy it is to install and maintain, and the level of noise it produces.

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About Patrice Alsteen

Patrice has been an animal lover, right from her childhood. She's currently enjoying the company of her cat, dog, aquarium fishes, and a few small furry companions.