Best 20 Gallon Canister Filters

Carol M.
Fisheries Consultant

An aquarium canister is a valuable piece of equipment for any fish tank for quality water management. A canister draws dirty water through a lift tube and pulls it out of the tank to a sealed external canister filter. The water inside the external filter runs through a cleaning process before the canister pumps it back to the tank. 

A canister is the best option to clean your tank and keep the fish happy. If you compare it with other filters, a canister won't cause a loss of water or fish. But, which is the best and most quality canister to choose? That’s what we will cover in this article. We have a list of the best 20-gallon canister filters for you to assess.

Best 20-gallon Canister Filters for Your Aquarium 

1. Fluval Canister Filters

Fluval is an exceptional canister filter suitable for both freshwater and saltwater use. This canister comes with a new design that has flex ribbed tubing. It has an amazing check valve along the drain to prevent flooding in case of a power outage.

Again, it has the best filter media capacity. Fluval features an instant prime system for quick startup and lift-lock clamps for easy access.

The disadvantage of the equipment is the lack of an adjusting valve to regulate the flowrate or even drain it when maintaining. The flex hose also prevents you from installing an inline heater.


  • It's black; thus easy to hide pipes in the tank
  • It has quality flex tubing
  • Instant priming
  • Very quiet motor


  • It’s a bit expensive
  • You can’t incorporate an inflow heater without modification.

2. Penn Plax Cascade Canister Filter

This  Penn Plax is another efficient and quality canister filter with great features. The product has a transparent body meaning you can see when it's filling up with water. The quick-release pipe allows you to easily disconnect the hose and prevent water from draining out of the tank.


Its valves can rotate at 360 degrees and fit under a tank stand. The filter also comes with mechanical filter media and activated carbon. It delivers crystal clear water to your tank at 100 gallons per hour.


  • Rotating valves can fit under the cabinet
  • Has filter media
  • It's transparent; thus, you can easily monitor it
  • It comes with an adjustable flow knob to regulate the flow


  • Lacks bio media
  • It can be a little noisy

3. MarineLand Magniflow Canister Filter

Marineland is a versatile filter for both freshwater and saltwater tanks. The canister offers a three-stage filtration. Aquarium water flows through the filter media to remove all dirt and particulate matter for your creatures’ safety at 160 gallons per hour.

The unit features quick-release hoses. Therefore, it's easy to detach the pipe when cleaning, and also, they are secure as they lock well. Another great feature is the clamps on the canister lid; they ensure convenience when using the canister.


  • It has all filter media
  • Quick-release hoses
  • Easy lid installation due to the presence of clamps
  • Easy to maintain the unit
  • Quiet operation


  • You may require the replace the bio balls
  • Lacks valve controls to regulate the flow

4. Eheim Classic Canister Filter

The unit comes with an elastic silicone sealing ring that ensures easy and safe closing. The product has sponges or loose filter media for the cleaning process. It has the following features, filter basket, spray bar, inlet pipe, and hose. It goes through two filtration stages at 116 gallons per hour.

However, the product lacks a priming button or level. If you need to prime the unit, you should detach the outflow and suck on the hose. Again, this canister lacks media trays; thus difficult to remove the media when cleaning.

 Nevertheless, the canister is durable and economical.


  • It has a friendly price
  • It's durable
  • Setting up the canister is straightforward


  • Difficult to maintain
  • Lacks media trays
  • Lacks priming button

5. UNS Delta Filters

This canister is suitable for freshwater and marine aquariums. The unit features filter media, inflow and outflow fittings, and tubing. You should mount this canister on the bank of the tank. This hang-on option is advantageous when dealing with a small tank and saves you the hustle of finding storage space.

The product has its filter media capacity, and it's flexible. It has a 150 gallons per hour flow rate and delivers the best results. Its also easy to set up, and maintain and offers quiet operation.


  • You can hang the canister on the back
  • Best for smaller aquariums


  • You may require to turn it down for certain setups.

6. SunSun Pro Canister Filter

This product offers great features giving you value for money. This canister has a UV sterilizer for algae, bacteria, and parasite control in the tank. It also offers a three-stage filtration process with a high flow rate.

This canister has an LCD that enhances your user experience. Again, with the LCD, you can regulate the pump's flow. The canister comes with an in-built UV that keeps your water and aquarium clean. The canister requires no priming to operate. It has flexible media trays to help you add other filtration systems like activated carbon, spores, and bacteria and give clear water.


  • High water flowrate
  • It offers 5 stages filtration process with a UV filter
  • It's economical with great features


  • UV is underpowered
  • It’s not adjustable

7. Aquatop CF Series Canister Filter

This canister has an amazing design to install in your aquarium easily. It improves your water quality by eliminating toxins and pollutants from the tank. The canisters feature a UV sterilizer to remove algae and bacteria. Again, it has a self-priming pump, three media trays, and a three-stage filtration system.

You can customize this canister to fit your preference and improve its efficiency. It can handle tanks up to 125 gallons. It's extremely quiet and handles  370 gallons of water per hour. You will have super clear water with activated carbon, ceramic rings, and bio-balls.


  • Strong and efficient filter
  • It's durable and keeps performing
  • Convenient self-priming pump
  • Allows to use your favorable filtration media


  • The UV lights can stop working

How to Choose the Right Canister Filter

Choosing the best canister for your aquarium is essential. There are factors that you should check to ensure you have the best canister, and they include:

  • Adaptability

Choose a canister filter to fit any aquarium tank and have easy installation. The unit shouldn't look out of place. It should reach maximum filtration potential.

  • Durability

Canisters are costly, so you should choose a unit that will serve you longer before thinking of a replacement.

  • Motor

It’s the heart of a canister filter. Motor pumps water into the filter for the filtration process. You need to ensure the canister has a robust motor that will run 24/7 without fail. Choose a motor with a UL rating to ensure it's up to standard. Again, the motor should be energy efficient.

  • Size of the Tank

Choose a canister filter that will be suitable for the size of your tank. It should handle the volume and flow of your fish. There is a general rule that you should choose a canister that can process four times the capacity of your tank (GPH/ gallon per hour).

  • Maintenance

Maintenance is another critical factor you should consider. A canister requires regular maintenance due to the biological load of the tank. The canister you choose should be easy to clean, with shutoff valves and other useful features.


A canister filter is a great investment for your aquarium. It aids in enhancing water quality for your fish tank. A canister will eliminate ammonia that makes your fish die. Also, those with UV sterilizers clear algae to improve water clarity and prevent oxygen depletion for your fish. From the list above, check out which brand of canister filter meets your needs.

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