When you set up your first fish tank, you will have to make some serious and practical decisions. These decisions will decide how much the fishes will be happy and healthy inside the aquarium. One of such important decision is to choose the right filter.

And you will have to determine which is better, “Sponge filter vs hang on back filter.”

In an ideal world, you would want both filters for your aquarium. But it isn’t possible,so you will have to determine which one you would pick. Take a look at our comparative discussion between the sponge filter and hang on back filter to decide which is better for what type of aquarium.

What Is Sponge Filter?

As the name suggests, a sponge filter is nothing but a piece of sponge. It is the fundamental of all filtration system. However, the sponge doesn’t work singly. It needs an air pump and tubing to work in a team.

The tube connects the pump and sponge for an integrated filtering mechanism. As the air pump uses the air pressure to push the water through the tubing, it comes to the sponge. When the water passes the sponge, it collects the debris to filter the water.

The sponge has pores, and the pore size will decide the debris size it will collect. The debris collection happens through a mechanical system. As the debris keeps attaching with the sponge, it later provides bacterial growth too.

What is (HOB) Hang on Back Filter:

A Hang on back, aka, HoB filter, will literally seat at the back of the aquarium and it remains invincible from the front side. The device will sit on the aquarium rim, and its box will be right at the back portion of the tank.  It also has an intake tube submerged inside the tank water.

The water travels through the tube to the filter and gets refined. The HoB filters are highly customizable and let’ you use all the three types of the filtration system with the best results. So, you will get the mechanical, biological and chemical filtering with the hang on back filters.


A Comparative Description of the Sponge Filter Vs Hob Filter


Sponge filter and hang on back filter both are beneficial for a fish tank. But they come with distinctive features that make them best for some applications and worst for some other applications. So, it is essential that you know the benefits and working system of these two filter and decides which one you would get.

Application and operational mode:

The sponge filters are the easiest to setup. However, you will need an additional plastic tube and an air pump to properly run the sponge filter. You will have to connect the air pump and the filter using the plastic tubing. The pump will sit right inside the aquarium.

When you plug in the air pump, it will start working immediately. It doesn’t need any priming at all.

On the contrary, you will have to plan appropriately to mount the hang on back filters. The tank must have sufficient room at its back so you can mount the filter there. Sometimes, you will have to adjust the aquarium to have the desired space between the tank wall and the tank.

During the power shortage or maintenance, the HOB filters will lose its suction. So, you will have to manually prime it each time after maintenance or a power cut. It can be hectic at times.

Capacity and filtration system:

If your tank is small to medium and has only a few occupants (read fish) the sponge filter will work the best. You can also use the sponge filter as a secondary filter with the canister or hang on back filters for even a better result.

Also, a sponge filter is useful for three special conditions. These situations are-

  1. If you quarantine a sick fish for treating it.
  2. When you have fries, you don’t want to get hem washed away inside the powerful HoB or canister filters.
  3. The sponge tank is suitable for breeding tanks when you want the fishes and their eggs to remain safe and sound.

A sponge filter initially offers mechanical filtering with the accumulation of debris. When it gathers sufficient debris, it provides biological filtration with bacterial growth.

The HoB filter is made for medium to large aquariums with several occupants in it. It is also an excellent choice for community tanks since it can control a large amount of water flow effortlessly. Also, it works best for the planted aquarium and if the tank has critters.

Since it is powerful, you need to setup a sponge or baffle right in front of it to control the water flow, if you want to use it for shrimps and Bettas. Also, the hang on back filter comes with specific tank capacity and GPH. It means you precisely know how much capacity you are getting.

Maintenance procedure:

Although it might sound ironic, Hob filters need less maintenance than the sponge filters. It is because the sponge pore will soon get clogged and stopped working due to debris accumulation. The cleaning frequency will depend on the tank occupants and how quickly it becomes dirty.

Typically, you will need to maintain and clean it at least once every two weeks. Luckily, the cleaning process is easy.

  • Slip off the sponge from the tank wall.
  • Use clean tap water to rinse the sponge correctly.
  • As algae and mineral will build-up on the sponge, you should replace it once in a year.
  • While replacing, use a small portion of the older sponge with the new one. It will help the faster bacterial growth with the new one.

The HoB filters, on the other hand, will need the least maintenance; not weekly care at least. It is recommended that you look at the hang on back filter to check its working efficiency carefully. Nonetheless, you will still need several days to find if the filter has stopped working.

  • You can clean the intake filter once every two weeks. It is essential so that the motor remains free of debris and works fine.
  • When you change water or clean the tank, you should clean and rinse the HoB filter. When water flow changes, you can still maintain the filter.
  • The filtering media will become loose in around four to six weeks. You will have to replace it once every two months.
  • Finally, you will have to replace the entire screening system once in a year to hang on back filters.

When you clean the hang on back filter regularly, the water frequency rate will change too. So, you will be freed from additional work pressure.


No doubt a sponge filter is cheaper than the hang on back filter. But we often forget that the sponge filter also needs an air pump and inlet tubing for proper functioning. Therefore, you will have to count its costing too.

So, when you consider such air pump and tubing costs, it might surpass an introductory HoB filter price. But if you have a large tank, HoB filter expense will be more than the sponge filters.

Sponge Filter Vs. Hang on Back Filter: Which One to Get

We have discussed the details of these two filter types essential for aquariums. But which one you should pick?  The following comparison table should help you in the final decision making.

FeaturesSponge FilterHang on Back Filter
TypeBasic filtering systemIt is available in a wide variety of sizes and filtering systems.
CompatibilityIt works best for the tank with 5 to 30 gallons of waterIdeal for tanks up to 50 gallons. For larger tanks, you will need multiple HoB filters.
EasinessIt needs no priming and so, is super-easy to use.It needs priming after each power cut and maintenance. So, using it isn’t easy.
Suitable forQuarantine tanks, breeding and fry. It offers a gentle water flow suitable for shrimps too.It suits a community tank and large tanks with several fishes. Also, it has a strong current.
Best ForWhen you medicate a sick fishIf you want customized chemical and mechanical filtration.
SpaceIt needs huge space inside the tankIt won’t occupy space inside the tank.

These are the best benefits of the two aquarium filter types. But aren’t there any disadvantage of these two filters?

Here’s take a look, in brief.

Sponge filter spoils tank space. You won’t get chemical filtration. So, you will have to clean the tank water frequently. The actual flow rate of the filter depends on the air pump power.

The hang on the back filter is suitable for large tanks mostly. So, you can’t apply it for small tanks. Also, it isn’t easy to maintain and install. It isn’t preferable for beginners. Also, priming whenever power shortage happens or maintenance can be tedious for busy people.


So, here’s our take on sponge filter vs hang on back filter.

If you are a beginner and starts with a small tank, always begin your aquarium career with the sponge filter. If you plan for fish breeding, use the sponge filter to allow the fish to settle. Also, it is safe for fish eggs.  Lastly, a sponge filter is a must for treating ill fishes.

When you have a large or community tank, the hang on back, aka, HoB filter is your only option. You can also use the sponge filter as a secondary option if the tank size is over 50 gallons. Also, it offers three types of filtering and consistent water flow.

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