Filters for a 30 Gallon Aquarium ( Makes, Models and Prices )

A 30 Gallon fish tank is the perfect step up size from the smaller aquariums that most people start with. However, you’ll need to start thinking about improving the size and power of the filter within the aquarium to cope with the larger water volume. A 30 Gallon aquarium can soon become smelly, look terrible and have poor water conditions if you don’t have the right filter installed.

As a responsible pet owner or fish keeper, you have a duty of care to provide the best possible living conditions for your pet fish to thrive in.

A Suitable filter in your aquarium you will not only look better, but it’ll help you enjoy the beautiful sight of a thriving home aquarium with healthy fish.

In this article: Filters For A 30 Gallon Aquarium. We’ll look at all the best possible filter options for your tank and narrow the search down to just 3 of the best type of filters for that size aquarium.

The fish equipment market can sometimes seem overwhelming and there’re so many makes and models to choose from, sometimes you just get lost in all the technical jargon.

So, Let us help you make the right purchase and find the most suitable filter for your 30 Gallon (135 Liter) Aquarium.

There’re four types of filters to look at on the market today that are suitable for a 30 Gallon Aquarium and these are the most commonly used filters. We’ll explain why these filters are the most popular and give you some Pros & Cons for each one.

Then we will give you a link to the most suitable filter for your size aquarium and direct you to the cheapest place we found for that filter online. This will save you time and money.

The Four most common types of 30 Gallon Aquarium filters are:

  • UnderGravel Filters
  • HOB (Hang On The Back Filters)
  • Internal Power Filters
  • External Canister Filters

For smaller aquariums we recommend just three options, but for slightly larger 30 gallon tanks you have an extra option of using an external canister filter. In our article: Filters for a 20 Gallon Aquarium we touch on this smaller type of filter in more detail.

What are Undergravel filters?

An undergravel filter is a plastic plate/sheet that is placed in the bottom of your aquarium and then covered with gravel. The water is drawn up through the uplift tubes along with bubbles from an air pump and an air stone. This pulls water from under the plate, which in turn draws water down through the gravel trapping dirt within the gravel. Then, mother nature takes over and the friendly bacteria that live within the gravel break down the dirt and fish waste.

This is one of the oldest methods of filtering a 30 Gallon aquarium and is tried and tested and works well. The only issue you will face with this method is that it really needs to be installed when the tank is new. Adding one to an existing aquarium is hard!

These come in all sizes so please check that one you need. You need one that covers the entire bottom of your aquarium.


  • Very effective
  • Inexpensive
  • Reliable and if the pump fails it’s easy to change
  • Natural way to filter an aquarium
  • Takes up no space in the aquarium
  • Out of sight


  • Cannot be added to an established aquarium without lots of mess and stress to the fish
  • Hard to clean
  • Gravel will become compacted and will need regular cleaning

What is a HOB filter?

A (HOB) Hang On The Back Filter is exactly what is says. A filter that hangs on the back of your aquarium.

The units can be added at any point which makes them suitable for most fish tanks.

All sizes available!

This unit hangs on the side or back of your aquarium and has one or two downpipes that reach into your aquarium. With the help of a motor in the HOB unit, water is drawn up the pipes which bring water and debris with it, this is then passed through a series of filtration media which physically and biologically capture and break down the fish waste and dirt. The C3 Model will be fine for a 30 Gallon aquarium but, the C4 model may make more sense if you’re ever going to increase the size of your tank as this model can filter 70 GPH. The link for both models are below.


  • Very easy to install
  • Easy to clean
  • You can use different types of media
  • Inexpensive
  • Various sizes available for all tanks


  • You need space at the back or side of the aquarium
  • The sound of running water can be annoying
  • Some are noisy
  • Can be difficult to prime and start going.

What is an Internal Power Filter?

These filters are the most popular, and have been for the past few years. Technological improvements have made them one of the most efficient methods of filtering an aquarium. Internal power filters will filter water for any fish tank of between 10-30 gallons.

They are plastic canisters that contain filtration media; this media traps the dirt and waste as it passes through the canister which is powered by a waterproof motor. They come in all different sizes and can be used in freshwater and saltwater aquariums.

It’s a very efficient and effective way to clean a fish tank for very little money. Easy to clean and easy to install, makes them one of the first choices to consider when buying a filter for a 30 Gallon (135 Liter) fish tank.


  • Easy to install into a new or established aquarium
  • You can use different types of filtration media
  • Inexpensive
  • Suitable for all size aquariums
  • Creates a lovely water flow within the tank which helps oxygenate the water


  • Take up space within the tank
  • Spoils the appearance of the aquarium
  • Gets your hands wet when cleaning
  • Have been known to suck up fry

External Canister Filters

External canister filters are large filtereation units that sit outside the aquarium. They draw the water out of the aquarium through outlet pipes which feed the water into the bottom of the cannister. The water is then pulled up through, often, several layers of filter media which traps the dirt and cleans the water.

The clean water is then returned into the aquarium using the pump inside the canister filter which is returned into the aquarium via an outlet pipe. This pipe can be placed anywhere in the aquarium and can be used to introduce a gentle water stream and current which will provide oxygen for your fish.

Oxygen is the number one contributing factor to fishes health. Read why it’s so important and what are the signs to look out for if your aquarium has low oxygen levels.

Then you can read how to increase the oxygen within your aquarium which will help your fish to thrive in a home aquarium.


  • Easy to clean
  • Physically removes dirt and biologically breaks it down
  • Easy to install
  • Effective method of cleaning
  • Suitable for large aquariums
  • Available in all sizes
  • Quiet
  • Out of sight
  • Add any type of media
  • Creates water movement so better for oxygen levels


  • Expensive
  • Takes up room under the aquarium
  • 2 Pipes need to enter the aquarium ( Inlet & Outlet )

What is GPH?

GPH stands for Gallons Per Hour and is the amount of water that passes through the filter every hour in Gallons.

The best way to know that you have a suitable filter for the size of your aquarium is to buy one that filters 110-120% of your water every hour. This will ensure sufficient water circulation and the best possible filter for the volume of water in your aquarium.

As an example, the HOB filter we have chosen is a 30 GPH filter. This means that your entire aquarium water will pass through the filter at least once every hour.

If You had a 40 gallon aquarium then we would recommend a filter around 50-60 GPH. I think you get the idea.

Conclusion: Best filter for a 30 Gallon aquarium

No matter which filter your choose from the list above, it will do the job. Simply buying a suitable filter will improve the chances of you having a healthier fish tank and enjoying the hobby more.

No one wants to see and smell a dirty fish tank. Yuck!

For more information on how to clean a fish tank filter without killing the good bacteria read our latest article on this topic.

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