Best Filter For 120 Gallon Aquarium: Reviews | Aquascape Addiction

Best Filter For 120 Gallon Aquarium: Reviews

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Need help finding the Best Filter For 120 Gallon Aquariums? we cover our top 5 powerful picks each reviewed in detail to help you decide.

Best Filter For 120 Gallon Aquarium: Reviews

A big 120 gallon aquarium needs a really powerful filter. The bigger your aquarium is, the more plants are inside of it, and the more fish are swimming around, the more powerful and effective the filter needs to be. We all know that any aquarium needs a good filter to remove waster, debris, pollutants, and other unwanted compounds. This is necessary in order to keep your fish alive and healthy.

Choosing the best filter for 120 gallon aquariums can be a real challenge. There are so many different options out there, all of which have different features, strengths, and drawbacks. That is why we are here today, to help you find a great filter for your 120 gallon tank (This is our top pick).

Fluval G6 Our Top Pick 9.8/10
Fluval FX4 Durable & Strong 9.3/10
Eheim Pro 4+ Very Quiet 9.2/10

What Kind Of Filter Do I Need For A 120 Gallon Tank

The bottom line here is that a big 120 gallon fish tank needs a big filtration system. Ideally you are going to get a big external canister filter. Sure, power filters, undergravel filters, and all of the other types make for OK choice, but only OK, not great.

Canister filters are meant to accommodate large aquariums because they themselves are large. Generally, they engage in all 3 major types of filtration, allow for lots of media customization, and can turn over insane amounts of water. For your big 120 gallon aquarium, an external canister filter is really the only viable option to go with.

What We Think Is The Best Filter For A 120 gallon Aquarium

Let’s take an in depth look at what we think is the best filter for a large 120 gallon aquarium. The below model is durable and highly efficient too (you can check the current price at Amazon here).

Fluval G6

One of the best parts about the Fluval G6 filter is that it is ideal for both saltwater and freshwater aquariums. Another thing that you might like about this particular filter is that it is very easy to use. It features a one touch self-priming feature so you don’t have to worry about priming yourself and actually getting it to start up.

Moreover, the 3 component drive pump provides you with great water flow, it is a very durable pump, and it is not loud either. You can also adjust the flow rate of the pump in order to suit the exact needs of your aquarium.

Another thing that you might like about the G6 filter is that it allows for easy access to the internal components. This allows you to easily monitor conductivity, the flow rate, and the water temperature as well. This particular model can actually handle larger aquariums of up to 160 gallons in size thanks to the fact that it can process a whopping 265 gallons of water per hour, which is more than enough to keep a 120 gallon aquarium clean.

Something else that we like about the Fluval G6 is that it is made with only high quality parts. It comes with a silicon gasket in order to make sure that it is sealed well and will not leak water, thus ensuring a long lifespan and ultimate durability. There is also the fact that the sleek design of it and the black color make it very visually appealing. What is really neat about this filter is that comes with HydroTech. This means that it has a great display screen which accurately monitors various water conditions and parameters to keep you constantly updated.

This filter engages in highly efficient three stage filtration. This means that it engages in mechanical, biological, and chemical filtration. It already comes with media included, plus it has the ability to allow you to control what kind of media you put inside of it.

It has a total of 3 media baskets for great filtration capabilities. The intake strainer on this model makes sure that no solid debris clogs the pump, plus you can attach spray bars and spray nozzles to it as well.


  • Very powerful – great for tanks up to 160 gallons.
  • Very durable with a solid seal for a no-leak experience.
  • Accurately monitors various conditions and parameters.
  • Monitors its own performance.
  • 3 stage filtration and 3 baskets for great filtration efficiency.
  • Allows for spray bars and spray nozzles.
  • Very quiet and efficient.
  • Reliable and well-built pump.
  • Adjustable flow rate.
  • Very easy to clean and maintain.
  • Looks great.


  • Takes up a lot of space outside of the tank.
  • May leak when tilted.
  • May generate an excessive amount of micro-bubbles.

Check the price at Amazon

4 Other Options That We Also Like: Reviews

Maybe the above filter is not the best choice for you for whatever reason, which is why we have 4 other great 120 gallon tank filter options for you.


One of the best parts about the API FILSTAR XP is that it is great for providing your tank with efficient and reliable 3 stage filtration. It engages in all major types of filtration including mechanical, chemical, and biological in order to keep your water clean and crystal clear. What is also pretty neat is the ability to hold up to 4 maximum capacity media trays, which means you can add a whole lot of media, plus you can be quite selective in terms of the types of media you insert into it. The inner dividers in the API FILSTAR XP allow for lots of flexibility which is another bonus.

The API FILSTAR XP comes with special BIO-CHEM ZORB technology. This is an exclusive research grade resin-carbon compound which is awesome for removing the smells, odors, and contaminants which basic carbon can’t deal with on its own. The pump and motor in this particular model are extremely durable and quiet at the same time. Moreover, the package comes with everything you need to engage in effective filtration, including flexible inlet and outlet tubes, suction cups, and a gooseneck. You can accurately control the volume of the water flow, plus you can control the output direction too.

The fact that the API XP can prime itself with only a cup of water is quite impressive too. You don’t need to siphon any water and you don’t need to pump it manually either. Also, the patented airlock system means that you don’t need to re-prime it, plus you can actually remove the canister without losing the prime.

This system also helps to prevent the overheating of the motor and pump for an increased lifespan. Also, the self-locking water shutoff system helps to prevent water overflow. This filter comes in 4 different sizes, with this one being the XL. This particular model can handle aquariums up to 265 gallons in size and can process and impressive 450 gallons of water per hour.

This bad boy comes with a large and wide rubber base to keep it stable and to dampen vibrations. Furthermore, this filter provides you with easy access to the internal components for easy maintenance and media adjustments. The heavy duty construction of this model is definitely a big selling feature.


  • Extremely durable.
  • Prevents leaks and overheating.
  • Adjustable flow rate.
  • Ideal for tanks up to 265 gallons – 450 GPH.
  • Easy prime feature.
  • Easy access to internal components.
  • Comes with a gooseneck for water direction control.
  • Great airlock system.
  • BIO-CHEM ZORB & 3 stage filtration for clean water.
  • Self-locking shutoff to prevent overflow.
  • Oversized baskets that can hold 4 media pouches.
  • Very quiet.


  • Takes up a fair amount of space.
  • Lack of spray bar.
  • Tends to suck in a fair amount of air.

Check the price at Amazon

2. Fluval FX4 Canister Filter

Yet another great option to go with, the Fluval FX4 Canister Filter is rated for aquariums up to 250 gallons in size. The FX4 Canister Filter can process around 700 gallons of water per hour. This is more than enough processing power to take care of heavily populated aquariums. Something that we really like about this model is that it is extremely durable. Everything included with the Fluval FX4 Canister Filter is made to last for a very long time to come. It comes with a very strong motor, which is combined with a reliable pump in order to provide you with optimal filtration power.

The Fluval FX4 Canister Filter engages in really efficient 3 stage filtration. Mechanical, biological, and chemical filtration are all performed by this particular filter. What is very impressive about the Fluval FX4 is that it can hold a whopping 4 liters or 1 gallon of media. It features several stackable and removable media trays so you can customize what kind of media the FX4 Filter holds at any given time. The stackable nature of the baskets helps to prevent water bypass for maximum water to filter media contact.

You might also like how the FX4 Canister Filter uses a smart pump system in order to monitor its own performance. It can actually adjust its own performance in order to suit the exact needs of your particular aquarium. Another neat feature is that this filter is self-starting, meaning that it primes itself. Simply add some water, plug it in, and the smart pump feature will do the rest. Probably one of the best parts about this filter is that you can put the output hose in the sink in order to engage in quick water changes. This means no more annoying buckets or siphons.


  • Incredibly great filtration – 3 stage.
  • Huge GPH filtration rate – 700 GPH.
  • Ideal for huge aquariums with a big population.
  • Stackable media baskets to prevent water bypass.
  • Huge media basket – 1 gallon – lots of media choice.
  • Extremely durable and strong.
  • Self-priming
  • Smart pump technology – self-monitoring performance.


  • Fairly noisy.
  • Very big – requires lots of space.
  • Hose connections may leak.
  • Not easy to access internal components.

Check the price at Amazon

3. Eheim Pro 4

This may sound a little weird, but the fact that the Eheim Pro 4 Canister Filter is made in Germany says it all. Simply put, the Germans make some really amazing technology and their products never fail to deliver. One of the things that many people like about the Eheim Pro 4 Canister Filter is that it is sleek and has a nice black color. Surprisingly enough, even though this model is very powerful and efficient, it does not require all that much space outside of your aquarium.

This filter can handle aquariums up to 160 gallons in size, plus it can handle well over 300 gallons of water per hour. What is also pretty neat is that the Eheim Pro 4 Canister Filter has a range Xtender function, thus effectively increasing the range at which it can take water in. This may not be the fanciest model around with the most features, but it works really well none the less. A big bonus for the Eheim Pro 4 Canister Filter is that it is whisper quiet so it won’t disturb your or your fish.

The Eheim Pro 4 engages in all necessary kinds of filtration including mechanical, biological, and chemical filtration. It has a large media basket with several removable and stackable trays. Being able to customize the type and amount of media you put in the Eheim Pro 4 lets you adjust it to perfectly adjust it to suit the needs of your aquarium. It has a whopping amount of media, included 2 mechanical trays, 2 bio trays, 2 sponges, and a chemical filtration aspect too.

The fact that the media trays are stackable means that it helps to prevent water bypass for maximum water to media contact. All filter pads and media comes included with this model, which is something that we definitely appreciate. Even better is that the easy access clips allow you to quickly get into the filter to maintain and clean internal components, as well as to change or replace filter media. The Eheim Pro 4 Canister Filter also comes with an adjustable flow rate feature so you can make it filter as much or little water as your aquarium requires.


  • Moves a whole lot of water.
  • Very quiet.
  • Very durable and long lasting.
  • Lots of room for media – 3 stage filtration.
  • Prevents leaching and leaking.
  • Ideal for large aquariums.
  • Easy to access the internal components.
  • Fairly space friendly.


  • Input and output tubing is very short.
  • Spray bar cannot be easily adjusted.
  • Fairly difficult to prime.

Check the price at Amazon

4. Hydor Professional External Canister Filter

This might be the final option our list, but it is certainly still a decent option. The Hydor Professional Canister Filter comes with everything you need to keep the water in your aquarium clean and crystal clear. First off, this particular model is built for both saltwater and freshwater use, which definitely makes like a lot easier.

The Hydor Professional Canister Filter can handle aquariums up to 150 gallons in size. It has the ability to turn over up to 345 gallons of water per hour. In other words, it has a very powerful pump that can filter great amounts of water. This model does have an adjustable flow rate, which is yet another thing that makes it one of the best options out there. The pump itself is extremely strong, reliable, and built for years to come, which can also be said about the motor which comes with the Hydor Professional Canister Filter.

We really like the Hydor Professional Canister Filter because it has a really sleek look. It’s fairly tall and narrow, which is great because it doesn’t require too much horizontal clearance on the outside of your aquarium. Another really neat part about this model is that it allows you to see inside of the filtration unit so you can see what is going on in there. The Hydor Professional Canister Filter does engage in effective 3 stage filtration. It does everything you need a filter to do including mechanical, chemical, and biological filtration. The stackable media trays allow you to customize the types of media on the interior for a whole lot of versatility.

Another thing that is convenient about the Hydor Professional Canister Filter is that it comes with an easy priming feature. Simply add some water, turn it on, and the Hydor Professional Canister Filter will do the rest. You don’t have to waste time and effort priming with this model. Moreover, the telescopic intake tubes make setting up the Hydor Professional Canister Filter about as easy as can be. This model comes with all of the seals and tech necessary to ensure that it does not leak or overheat.


  • Great for larger aquariums – heavy flow rate.
  • Durable and sleek.
  • Doesn’t need too much space.
  • Water flow control.
  • Telescopic intake tubes for versatility.
  • Effective 3 stage filtration – allows for easy media changes.
  • Easy priming feature.
  • Comes with everything you need.


  • May clog on occasion.
  • Top is somewhat hard to remove.

Check the price at Amazon


At the end of the day, as long as you get a good, strong, and reliable 3 stage external canister filtration system (like this one, which is our top pick), your 120 gallon tank should be very clean. The best filter for a 120 gallon tank is one that can turn over the water several times per hour, removes all impurities, is quiet, and doesn’t take up too much space, not to mention that it needs to be durable too. We would definitely recommend checking out any of the 5 above options as they are in our opinion some of the best.