Best Filter For 40 Gallon Tank – Review & Buying Guide

Best Filter For 40 Gallon Tank – Review & Buying

You are probably wondering what the best filter for a 40 gallon tank is. Fortunately, there are many options out there, but it can be overwhelming to know which one to choose. But, fear not, we’re here to help!

We’ve compiled a list of some of the best filters for this size tank and will tell you why they’re so great! So let’s get started, shall I?

However, in case If you don’t like to read all the product comparisons, you can pick one from my top three picks:

What type of filter is suitable for a 40-gallon tank?

If I categorize the types of filtration systems available for aquariums, the list should look like this:

  •  Sponge filter
  •  undergravel filter
  •  canister filter
  •  internal submersible filter
  •  hang on the back filter
  •  sump filter

Now the question is, what type of filter is suitable for a 40-gallon tank? You can use any type of filter listed above except the sum filter. The reason is the setup for the sump filter is quite costly, and it suits best with saltwater aquariums.

Sponge Filter:  Operation and maintenance of a sponge filter are straightforward. And If you use sponge filters, you probably need multiple units to keep tank parameters in balance. The reason is that the sponge filter is clogged very quickly, and you need to clean that very often. So, buying an additional unit will give you some maintenance space and help keep the tank parameter stable.

Sponge filter in a nutshell

Undergravel Filter: Undergravel filter works well in small planted tanks, and it provides the best biological filtration. However, deploying an undergravel filter as a standalone one is relatively uncommon because of its weak chemical and mechanical filtration. 

Since undergravel filters are beneficial in many ways, you can use them in your tank, but I will suggest a combination with the power filter

Undergravel filter in a nutshell

Power Filter: Power filters are of two types: hang-on back (HOB) and internal submersible filter. You can use any kind, but HOB filters are more robust and powerful than an internal submersible one. Basic operation is pretty similar and provides three-stage filtration. 

Power or HOB filter in a nutshell

Canister Filter: The best option for you would be a canister filter. Although canister filters are not easy on the wallet, it provides superior filtration than any other types. As a result, you will get clean and healthy water, and at the same time, maintenance frequency will be less. However, when it’s due for maintenance, it demands meticulous effort. 

Canister Filter in a nutshell

Best Filter For 40 Gallon Tank: Review

1. Penn Plax Aquarium Cascade 700 Canister Filter

Penn Plax Aquarium Cascade 700 Canister Filter produces up to 185 GPH flow rate and can take care of 65-gallon tank size.

The Cascade 700 is a quick push-button self-priming filter that can be used in both freshwater and marine aquariums.

An adjustable flow control valve allows you to adjust the low, medium, or high water flow rate.

Its large media baskets allow you to customize the media and ensure effective three-stage (Mechanical, Chemical, and Biological) filtration. 

This three-stage filtration system includes everything you need to get started, including a spray bar, adjustable flow control valve, two media baskets, and start-up filter media.


  • Easy to install.
  • Durable and reliable.
  • Adjustable flow rate.
  • The large customizable media basket.
  • Push-button quick priming.


  • Some users mentioned the flow bypass issue.

2. MarineLand Magnum Polishing Internal Canister Filter

The Magnum Polishing Internal filter is an excellent choice for aquariums up to 97 gallons. It features a large dual-chamber media basket that allows you to customize the filtration.

It provides additional water polishing and three-stage filtration, thanks to the micron filter cartridge included in the package.

The efficiency you can expect is similar to a canister filter. However, few users mentioned that filter cartridges block too early and may need replacing every few weeks. 

Different opinions on how noisy the filter exists: some experienced noise over 50 DB, but others find it extremely quiet.

With the included start-up filter media, this filter can be used for both fresh and saltwater aquariums. It’s also great for planted tanks!


  • Extra water polishing.
  • Large media chamber.
  • Diatom can be charged with the micron cartridge.
  • Responsive customer care service.
  • Usable to all aquarium setups.


  • Filter cartridges get clogged early.
  • Some users found it noisy.

3. Fluval 206 External Filter

The Fluval 206 external filter is a self-priming, quiet filter that offers a lot of bang for your buck. This aquarium filter has an impressive filtration capacity and can handle tanks up to 45 gallons in size. 

It comes with multiple media baskets packed with all necessary filter media. Big baskets also make it easy to customize filter media according to your preferences. 

The Fluval 206 External Filter comes with adjustable flow control on the top of the aquarium, which allows you to adjust the amount of water being pumped into your tank. 

This filter also has a removable lid for easy cleaning. However, when it comes to cleaning the canister filter, it’s a big task, although maintenance frequency is less. If you are a beginner, you may find it difficult to clean.


Self-priming pump.

Super Quiet.

Multiple media chambers.

Adjustable flow.

Arrangements were made for simple cleaning.


  • Cleaning is difficult for beginners.

4. Penn-Plax Cascade 600 Submersible Aquarium Filter

Penn-Plax Cascade 600 Submersible Aquarium Filter is a great choice for your aquarium. This filter comes with a spray bar option allowing you to distribute water evenly in your tank. In addition, you can adjust and change the flow direction as per your demand. 

The filter is a reliable, energy-efficient aquarium filter that cycles water at 175 Gallons per hour (GPH) quietly for tanks up to 50 Gallons in size. 

You can choose filter media and customize it according to the tank’s needs. It’s great for freshwater, saltwater aquariums, even in turtle tanks where bioloads are high. 

You’ll get everything to get you started, including the necessary filter media. You need to mount the filter using the provided suction cups, and you can place the filter horizontally as well to remove it from view.


  • Whisper-quiet operation – ideal for bedrooms or offices!
  • Energy-efficient! 
  • Easy to clean and maintain. 
  • Robust but adjustable flow rate.
  • Can be positioned vertically or horizontally.


  • Some users find it becomes noisier over time.

5. Penn Plax Premium Under Gravel Filter System

Penn Plax Premium Undergravel Filter System is an easy-to-install aquarium filter that helps keep your fish tank clean. 

The Penn Plax under gravel filter features filter plates, lift tubes, carbon cartridges, and air stones. The package comes with clips to attach the plates securely. The extra-large lifting tube is adjustable to get custom filtration. 

This aquarium filter system is suitable for freshwater or marine tanks. It’s been designed to use in aquariums for 40 to 55 gallons. 

The carbon cartridges remove odor and water discoloration as well as ensuring chemical filtration. You need to place them at the elbow section of the lift tubes. 

A highly porous air stone is included with this package for use with an air pump; however, you’ll have to buy tubing and air pump separately!


  • Simple installation.
  • Carbon cartridges and air stones are included. 
  • Suits in both freshwater and marine water tanks.
  • Adjustable lifting tubes. 


  • The air pump and air tubing aren’t included.
  • Plate connectors are not robust, can break if mishandled. 

6. Seachem Tidal Power Filter

Seachem Tidal HOB filter is an all-in-one aquarium system that provides outstanding filtration for freshwater or saltwater tanks up to 55 gallons, and it’s one of the best HOB filters in the market. 

The Seachem Tidal HOB filter combines mechanical, chemical, and biological filtration into one compact unit. Also, it features a unique surface skimmer that helps to remove white films from the water. 

The pump used in the filter self-primes, which is a great benefit during power outages, especially when you’re not at home. 

The media box is customizable and spacious, allowing you to add any type of media you like (carbon, bio balls) to your liking. Moreover, you can’t forget the routine maintenance because a blue pop-up indicator will notify you when it’s due. 

It has an adjustable flow rate, and the water doesn’t bypass the media, which means it will be clean for longer! In addition, this product is extraordinarily quiet, and it also comes with a three-year warranty from the manufacturer.


  • Equipped with a surface skimmer.
  • Self-priming pump.
  • Spacious customizable media box.
  • Adjustable flow .
  • No water bypass.
  • Superbly quiet.
  • Highly reliable. 
  • Three-years warranty.


  • Comparatively larger than other HOB’s.
  • Some users find it difficult to remove the pump cover for maintenance. 
  • Small fish can suck in the surface skimmer.

7. Huijukon Air Driven Sponge Filter Aquarium

If your sponge filter keeps the whole house awake, you can give Huijukon a shot. This one is tranquil and leaves behind beautiful streams of tiny bubbles–I recommend it for tanks with bettas, snails, shrimps, crayfish turtles, fry discus, and angelfish.

Huijukon Bio Sponge Filter is an excellent choice for a 40-gallon tank. Featuring two 9-layered, high-porosity sponges and two bio-media containers, this aquarium filter provides an ideal environment for beneficial bacteria to grow and thrive. 

Apart from effective biological filtration, it also traps floating wastes large debris to keep the aquarium pristine. 

The adjustable air-water outlet allows you to change the filter height and direction to customize your water circulation. 

Maintaining this sponge filter for aquariums isn’t difficult: It’ll last over a year and provide good value. 


  • Oxygenates the tank and promotes healthy fish growth.
  • Sponges are highly porous, which offers better bacteria colonization.
  • Two bio-media containers for additional biological filtration. 
  • The air-water outlet is adjustable. 
  • Suitable for fish tanks for 10 to 60 gallons.


  • Average quality bio media, but you can easily customize it with something of better quality. 

How to Choose the Right Filter for 40 Gallon Tank

Filtration Types:

The aquarium filter does the filtration job in three ways. It removes debris from the aquarium water, eliminates odors, toxins and houses beneficial bacteria that convert ammonia into nitrates.

Undergravel filters and sponge filters are not good at chemical and mechanical filtration (removing toxins, odors, debris). But they perform biological filtration effectively.  

You should buy a filter that can do all three jobs. The canister filter and power filter can do the three-stage filtration effectively. Among them, a canister filter is best for doing heavy-duty work. 

Filter flow rate: 

The aquarium filter should have an adequate water flow rate to keep the tank parameters in a reasonable range. The improper water circulation will hamper the filtration. 

The aquarium filter should have a minimum water flow rate that is four times the size of your tank. For example, for a 40-gallon tank, it needs to be at least 160 gallons per hour.

Frequently Asked Questions

How to do maintenance of the filter? 

Some aquarium filters require more maintenance than others, depending on the tank’s bioload. The regular upkeep of your filter is significant for ensuring it performs to its maximum capacity. In addition, since filter media lose their efficacy over time, a timely replacement is necessary. 

Ceramic rings and coarse foams will need to be replaced when they fall apart or create bigger pores. In contrast, actuated carbon should only be changed after it has lost its efficiency within half a month to an entire month of use.

Apart from replacement, another job you have to do is cleaning the media. Sponges, filter floss require cleaning weekly or bi-weekly, depending on the debris accumulation. Bio-media like ceramic rings or bio-balls need to be cleaned when blocked, probably once in six months. Carbon media requires only replacement, not cleaning. 

Make sure when you wash the media in your tank water instead of tap water, because tap 

water may contain chlorine which may lead to losing beneficial bacteria during cleaning

Can I use filter media of my own choice?

Not all aquarium filters allow you to customize the filtration by using your preferred media. However, in general, you can use your preferred media in most canister and HOB filters. The reason is they hold filter media in a separate compartment where you can place media of your own choice.

However, you should check before purchasing if the filter is customizable or not.

Can I use two filters in one tank?

If you want to use more than one filter in the tank, feel free. However, it is not necessary as long as you choose the right filter from my list above.

Still, if you would like to opt for multiple units, you can buy two filters rated for 20-gallon tanks instead of a single unit. 


The last thing you want is to spend your time and money on a filter that doesn’t work. There are too many options, so it’s important to know what features to look for when shopping around. 

I hope the review of the best filter for 40-gallon tanks and guide on how to choose will be a tremendous help for you. Still, if you’re not sure which one will be best for your needs, leave us a comment below!

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