Aquarium using best hob filter

Best HOB Filter: Hang on Back Filter Options

Maintaining clean water in your fish tank is essential for your tank inhabitants’ health and well-being, but it can be challenging to manage water quality in aquariums. Without proper filtration, tank water can quickly become polluted with dangerous and potentially deadly chemicals. By using the best HOB filter on the market, you can keep your fish tank water clean and pristine. Our favorite HOB filter is the AquaClear Aquarium Filter.

Hang-on-back (HOB) filters are easy to install, require little maintenance, and can help keep your water clear and healthy for your fish. We tested many products and put together these reviews of our favorites to help you choose the best option for your aquarium and budget.

Recommended HOB Filters:

What is the Best HOB Filter?

Our all-around favorite HOB filter is the AquaClear Aquarium Filter. It’s super simple to mount to your tank, does an excellent job of limiting debris and harmful chemicals in your water, and comes in a variety of sizes to meet your tank’s needs.

What is a HOB Filter?

A hang-on-back (HOB) filter is the most common and widely available aquarium filter type. They are our favorite type of filter because they’re easy to use and affordable. They typically clip to or hang on the rim of your tank and use a pump to move water through the filtration media inside the filter.

How Does a HOB Filter Work?

A HOB filter pumps water from your tank into the filter chamber. After the intake of water, there are typically two compartments in the chamber, each with different media.

Most HOB filters include a sponge or other physical filter (like filter floss) in the first compartment. As the tank water passes through the filter, physical debris gets caught and removed from the water.

canister filter keeps aquarium clean

The cleared water then moves into the second internal filter compartment, which usually houses biological filter media. Most aquarists use either bio balls or ceramic rings in this section of the filter. The biological filter media house an immense number of beneficial bacteria. This good bacteria will consume unwanted food and ammonia from fish fecal matter.

Once the water has been scrubbed clean of physical debris and dangerous chemicals, it pours out of the return and back into your tank.

HOB filters are also cool because you can stage non-aquatic plants like pothos in the outflow area for a beautiful addition of greenery to your tank.

Why Do You Need a HOB Filter?

Filtration is required in all fish tanks, no matter the size. Without a good HOB filter, your tank water will hold ammonia, nitrites, and nitrates, all of which can harm and even kill your fish.

HOB filters not only help keep your water clear and appealing by removing fine debris but they also house bacteria to remove deadly chemicals that naturally build up in your aquarium as fish eat and carry out metabolic processes.

How to Choose a HOB Filter for Your Aquarium

When you’re deciding on which hang-on-back filter to get for your tank, make sure you consider the below factors.

1. Required Flow

Your tank water should be turned over at least once every hour to reduce cloudiness and avoid the build-up of harmful chemicals in your water. As such, you should choose a filter with a flow rate that is equal to or greater than your entire tank volume.

For example, a HOB filter with a 50 gallon-per-hour (GPH) flow rate won’t be sufficient for cleaning a 65-gallon tank, but it will be suitable for anything up to 50 gallons, provided it’s rated for that volume or higher. Required water flow is an important feature to consider.

2. Size of Tank

In addition to your flow rate, you need to match your filter to your tank’s volume. The volume rating of a product will give you an indication of the fish load the filter can handle.

Filters with higher volume ratings are more powerful and have better filtration capacity, so they’re able to clean larger tanks. Provided the flow rate is also appropriate, a filter rated for a 120-gallon tank can sufficiently clean the water of an appropriately stocked, 120-gallon tank and leave your fish with clear, healthy water.

3. Media Type

Not all HOB filters accept the same media, so you’ll need to choose a filter that matches your setup and the type of filtration you plan to do.

Most HOB filters include physical or mechanical filtration, like a sponge or filter pad, as well as biological filtration, with bio balls or ceramic rings.

Some more expensive products have space for activated carbon to carry out chemical filtration or a water scrubber to keep your tank crystal clear. Some options even include UV filtration to kill off diseases, protozoa, and fungi in your water.

For the best filtration possible, choose a HOB filter with added compartments and media capability.

4. Price

Owning and maintaining aquariums is costly, so you should carefully consider the price of the HOB filter you’re considering. Filters vary in cost based on the size of the tank they can handle, their durability, and the number of filter media they can house. If you’re looking for the quietest filter, you will probably need to pay a bit extra for the lack of noise.

If you have the money, choosing a filter that is a bit overpowered for your tank is typically best. A HOB filter designed for a 120-gallon tank will be under minimal stress in a 60-gallon tank and maintain the healthiest water possible for your fish.

5. Reviews

Lastly, you should read the online reviews of a HOB filter you’re considering to get a sense of how accurate the volume rating is and how durable the filter will be overall.

Some filters that are rated for 50 gallons may struggle to maintain a tank of that size and fail relatively quickly under the pressure. The ratings are a bit subjective, so the reviews will help guide you to the ideal filter for your tank.

Differences Between a HOB and Canister Filter

HOB filters and canister filters generally use the same principles and the same media to filter your aquarium. Most use mechanical and biological filtration, and specific models of both types can accommodate other methods, like UV or chemical filtration.

Canister filters are almost always more expensive than HOB filters, but the most significant difference is that canister filters sit outside your tank. Most aquarists place them in their aquarium stands and route clear hoses from the tank to the filter. This can be an important element of design to consider when making the HOB versus canister decision. Do you want a visible filter or would you prefer a hidden filter?

You can often install in-line heaters and other accessories like spray bars on canister filters, but a HOB filter can’t usually accommodate these.

Best HOB Filter Options

After extensive testing on our own aquariums, we’re confident that the below HOB filters are the best ones available. We’ll offer a brief list followed by in-depth reviews below.

1. Our All-Around Recommendation: AquaClear Aquarium Filter

This filter is extremely reliable and made with durable materials, so we’re confident it will last for many years.

It comes in various sizes for tanks ranging from 5 gallons all the way up to 110 gallons, so you can customize it based on your setup.

It has compartments for mechanical, biological, and chemical filtration. It comes with filter media, so you can set it up right out of the box.

It’s relatively quiet during operation but still provides excellent cleaning capability.


  • It includes filter media to get you started right away
  • It features compartments for mechanical, biological, and chemical filtration 


  • It filters very efficiently
  • It has an adjustable flow rate to customize to your set up
  • It comes in different sizes
  • It’s affordable


  • It’s rather bulky
  • The flow rate may be too high for fish sensitive to water movement

2. MarineLand Penguin 350 HOB Filter

This filter comes in sizes rated for tank volumes between 75 and 350 gallons. It’s ideal for larger tanks and might be unnecessarily costly for tanks under 30 gallons.

Even the smaller sizes are capable of very impressive flow rates, making them suitable for crowded tanks or aquariums with large fish that produce a lot of waste.

It includes compartments for mechanical, biological, and chemical filtration, and it does an excellent job of maintaining clear, healthy water for your fish. However, it cannot accommodate UV filtration.

It’s very affordable, and it includes filter media.


  • It uses a patented bio wheel for ideal biological filtration
  • The powerful pump can cycle over 300 gallons per hour


  • It’s a very reliable, consistent filter
  • It includes filter media to get you started right away
  • It can handle mechanical, biological, and chemical filtration
  • It’s very affordable


  • It’s a bit noisy during operation
  • The flow rate may be too high for fish sensitive to water movement

3. Fluval C4 Power Filter

This filter is highly reliable and durable, and we’re confident it will power through cleaning your tank for years.

The C4 model is rated for tanks between 40 and 70 gallons, but other models can be used for smaller tanks if needed. You can adjust the flow rate to match your tank size and optimize filtration.

It has compartments for mechanical, biological, and chemical filtration.

It’s a bit on the pricey side, but it does include filter media to keep additional costs to a minimum.


  • It features a 5-stage filtration process for clean, clear water
  • The flow rate adjustment can be used to tune the filter to your tank size and load


  • It provides efficient, reliable filtration
  • It’s very durable
  • It includes filter media for immediate setup


  • It’s a bit expensive
  • It’s rather bulky

4. MarineLand Emperor Filter

This filter comes in sizes that can clean aquariums between 5 gallons and 90 gallons. They all have excellent flow rates, the largest of which peak at around 450 gallons per hour.

It has compartments for mechanical, biological, and chemical filtration, and it does an excellent job of scrubbing your tank water clean.

It only comes with mechanical filter media, so you’ll need to purchase biological and chemical media separately.

This filter is very expensive, and the added cost of media can easily put you over budget.


  • It uses a biological filter wheel that improves filtration
  • The powerful pump has an excellent tank turnover rate


  • It can accept mechanical, biological, and chemical filter media
  • It is durable and likely to last for years
  • It’s ideal for crowded tanks or those with large fish


  • It’s rather expensive
  • It doesn’t include all of the media you need

5. SeaChem Tidal Power Filter

This HOB filter comes in just one size for 55-gallon tanks, so it’s not ideal for small aquariums or those over 55 gallons.

It has space for mechanical, biological, and chemical filter media, but there are only two compartments. This will make chemical filtration a bit less productive than in other filters. It only includes mechanical and biological media.

It’s a bit on the pricey side for the size, but it does have some nice features, like an adjustable flow rate to tune to your tank and relatively quiet operation.


  • It has space for plenty of filter media
  • It includes a flow rate adjustment knob for customization to your tank


  • It can accommodate mechanical, biological, and chemical filtration
  • It’s relatively silent during operation
  • It comes with mechanical and biological media


  • It doesn’t include chemical filtration media
  • It’s expensive

6. Penn Plax Cascade 150 Filter

This filter comes in various sizes for tanks between 20 and 300 gallons, meaning it can handle a small tank to a large tank. The flow rate is sufficient at each size, and it’s adjustable, so you can tune it to suit your tank and fish.

It can accommodate mechanical, biological, and chemical filtration. It only takes replaceable cartridges, which will increase your cost over time and limit customization options.

It’s very affordable, but it isn’t quite as efficient at clearing the water and maintaining healthy chemical levels as many other options we tested.


  • The adjustable flow rate makes it tunable for your setup
  • The large compartment has space for mechanical, biological, and chemical filtration media


  • It comes in various sizes for up to 300-gallon tanks
  • It comes with media
  • It’s very affordable


  • It’s not as efficient as other options
  • It only accepts media cartridges, which can get expensive

7. Aqueon QuietFlow Filter

This filter only comes in one size for 90-gallon tanks, so it will be unnecessarily expensive for most tanks under 50 gallons.

It has space for mechanical, biological, and chemical filtration, and it does a decent job of cleaning up the tank water. However, it only accepts disposable cartridges, so you’ll end up spending more on media over the long run with this filter.

It’s somewhat pricey, but it does come with two media cartridges to get you started.


  • The multi-stage filtration does a good job of cleaning the water
  • The replaceable cartridges make cleaning a breeze


  • It uses mechanical, biological, and chemical filtration
  • It includes media cartridges to get you started


  • It only comes in one size
  • It only accepts disposable media cartridges

How to Set Up and Maintain a HOB Filter

Setting up a HOB filter is as easy as resting it on the back rim of your tank and plugging it in. You’ll have to add media for filtration, which is best done in the following order from top to bottom: mechanical, biological, chemical.

To keep your HOB filter running properly, you’ll need to clean it every time you do a water change, about once every other week. Remove any mechanical filtration media and rinse it thoroughly before placing it back in your filter. Remove biological filter media and place in a small container with tank water. Swirl the media around to remove debris and algae before placing them back in your filter.

Chemical media, like activated carbon, should be replaced about once a month. Specialty water scrubbers can be swapped out as needed or every two weeks.

If you’re using any filter cartridges, be sure to change them per the manufacturer’s recommendations.

How to Improve HOB Filter

HOB filter performance can be improved with a few small tweaks. You can buy bulk carbon, sponge/s, or filter floss and cut them to fit inside. This will add additional filtration and polishing capability to your filter. You can also add bags of bio-media, peat, Seachem Purigen or other media types internally to boost filter performance.

HOB Filter FAQs

Are HOB Filters Good?

Provided you maintain them properly and use the appropriate size and media for your tank, HOB filters can provide clean, healthy water for your tank for years.

How Often Should I Clean My HOB Filter?

You should clean your HOB filter about once every two weeks. Most aquarists find it easiest to do their filter cleaning during routine water changes.

How Do I Know If My Fish Filter is Working?

Your filter should be keeping your tank water clear and free of debris, so clean water is a good sign of a functioning filter. However, you should test the levels of toxic chemicals in your water that your filter should be removing. Use a water testing kit to monitor ammonia and nitrite levels carefully. Minimal levels of these compounds indicate that your filter is working as intended.

Can a HOB Filter Be Used for Saltwater?

Hang-on-back filters work wonderfully in both a freshwater tank and saltwater tank, as long as they use mechanical, biological, and chemical filtration.

Can You Rinse Fish Filters?

Yes, you can. The mechanical and biological media benefit from rinsing during the cleaning process. It’s best to rinse biological media in tank water to help preserve the beneficial bacteria housed inside it.


HOB filters are an excellent way to keep your tank water clear and reduce harmful and potentially deadly chemicals that otherwise build up in your aquarium. They’re often cheaper than sump pumps and canister filters, they’re super simple to set up, and they’re typically a breeze to clean.

Our all-around recommendation for a HOB filter is the AquaClear Aquarium Filter. It uses a variety of filtration methods to keep your water healthy and clean, it includes media to get you started, and it runs efficiently and reliable in tanks ranging from 5 to 110 gallons. It will meet the needs of the average aquarium hobbyist.

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