Fluval FX4 Canister Filter Review

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To properly maintain a large aquarium, it’s going to take more than a run-of-the-mill filter to get the job done.

The right filter will need to conduct a deep clean that gets rid of debris, removes harmful chemicals and substances, all while cycling through large amounts of water all day, every day. In short, this filter needs to be powerful.

Fluval is a well-known brand famous for delivering high-quality filters that clean out large tanks with ease and efficiency. The Fluval FX4 Canister Filter is the “little sibling” to the FX5 and FX6, and lives up to the prestige of this brand by delivering the same amount of power despite its smaller size.

fluval fx4 review

Perfect for both freshwater and saltwater aquariums, the FX4 comes equipped with a slew of features that’ll bring out the best in your tank.

But no filter is without fault. Here we break down the good and the bad, so you can make the best buying decision.

Fluval FX4 Canister Filter: The Details


  • Weight:1 lbs.
  • Dimensions: 6 x 15.6 x 17.7 in.
  • Filter Capacity: 250 gal.
  • Media Stages: Mechanical, chemical, and biological
  • Self-Priming or Standard: Self-priming
  • Warranty: 3-year warranty


The Fluval FX4 Canister Filter boasts a wide array of features, making it one of the top filters on the market.

These features contribute to great performance and ease of maintenance, so that aquarium owners can rest easy knowing that their tanks are being well taken care of.

fluval canister filter

No Clogging

Clogging can mean the end of an otherwise good filter, so Fluval planned ahead just in case.

This filter comes equipped with an anti-clog strainer that ensures that water keeps flowing.

Smart Pump Technology

Don’t you wish you had a filter that was smart enough to maintain its own efficiency? Fluval shares your feelings.

A unique feature of the Fuval FX4 is its use of smart pump technology. The filter is made to stop every twelve hours, allowing any trapped air to escape, then it restarts again.

This allows the device to maintain optimal filter performance without you having to lift a finger.

Customers who don’t know this may be alarmed at first, but don’t rush to return the device; this is what it’s supposed to do. You’d be missing out on a great buy.


Priming a filter can lead to more work than you’re bargaining for, but the FX4 has got this covered.

Starting the device is simple – just add water. Literally!

Once you add water and power it up, the filter will automatically start and prime itself, readying it for immediate use.

Energy Efficient

It goes without saying that a powerful filter can be taxing on energy consumption, which can also be taxing on your energy bill.

The great thing about the FX4 is that uses 10% less power than previous models, making it both an energy saver and a money saver.

This is also something to consider if the price point happens to be a little startling.

Leak Proof

The FX4 is designed with large locking clamps that secure the motor and canister in place, preventing leaking.

If pooling water was an issue with previous filters you’ve owned, then you won’t have to worry about getting your floor and feet wet any more.

Three-Stage Filtration

Any filter worth their salt will include a three-stage filtration system to truly rid your tank of grime, impurities, and harmful chemicals.

This filter is no different, but it has the added bonus of being able to filter 700 gallons of water per hour.

This device truly works hard so that you don’t have to.


The FX4 comes with easy to remove, stackable media baskets that eliminate excess water bypass.

Not only that, but these baskets can hold up to 3.9 L of media, making for thorough three-stage filtration.

Water Changes and Gravel Cleaning

This filter has no issue conducting water changes – it drains and refills the water right from the utility valve. So if you’re worried about heavy lifting, worry no more!

Cleaning gravel is a pain because there is so much waste that accumulated between the grains. Imagine manually cleaning 250 gallons worth of gravel – you’d shudder to think about it.

When you connect the hose to this utility valve, located at its base, the filter does the rest of the work.

Fluval FX4 Canister Filter Review

The Positives


Fluval didn’t cut corners on this product. The materials are well made and durable to ensure that this filter lasts a long time.

With the FX4 Canister Filter, you won’t have to worry about cheap parts or the device breaking down, and should something happen there’s a warranty to cover it.


What good is a filter – or any product for that matter – if you can’t trust the manufacturer to accommodate any future damages?

Thankfully the FX4 comes with a three-year warranty to cover parts and issues that may arise. Along with its sturdy design, you can rest assured that if the device malfunctions (through no fault of your own, of course), you can have it fixed for years to come.


The whirring sounds of your aquarium can be soothing to some, but can cause minor noise pollution to others.

Thanks to the help of Fluval filter’s rubber feet, you won’t have to hear any noise while it operates.

Now your aquarium can be seen and not heard which is a total bonus for those who are sound sensitive.

Customizable Flow

You are already promised a powerful flow with the Fluval FX4, but this filter also makes that flow customizable.

The filter includes multi-directional output nozzles so you can easily control just where that flow goes.

Everything is Included

If you’re new to the game, you can be easily overwhelmed by the many products and media offered in stores or online.

Thankfully the Fluval FX4 comes with everything needed to get you set-up and going in no time.

All media is included (mechanical, chemical and biological) with the filter so you can skip the process of scouring your stores and you can skip the added costs of buying them separately.

Another way Fluval makes life a little easier.

best canister filter

Designed for Ease of Use

Nobody wants to deal with a cumbersome filter no matter how good it looks or how powerful it is. Luckily, the FX4 was created with this in mind.

It’s designed with valves positioned at 45 degree angles for easy installation and rotation leaving the fussing at bay.

Additions like rubberized feet for quiet operation, multi-directional output nozzles for customized water flows, and a utility valve with a drain hose for easy canister flushing.

Whatever issues aquarists have had in the past, the FX4 accounts for…and then some.

Easy Set-Up

It would be surprising if the Fluval FX4 was a pain to set-up after all the features it includes.

Set your worries aside because that is far from the case. This filter is quick and easy from start to maintenance.

It will usually take just minutes to set up from out of the box and the FX4 comes with a long manual with diagrams if you do get a little lost.

Thanks to mentioned features like the included media, self starting, and smart pump, your tanks and aquariums will be crystal clear in no time.

Here’s a video showing a cleaning of the Fluval FX4 Canister Filter.



The Negatives

It’s Bulky

The FX4 is smaller than the FX6, but this doesn’t mean it’s compact.

It’s pretty big and bulky since it’s as long as it is wide, standing at over a foot tall. You will need to put it under your aquarium setup for it to fit.

If you’re concerned about space, then you might want to reconsider getting this filter.

This isn’t to say that you can’t make the size work, but if it can’t…then it can’t.


You love your aquarium; it makes you happy to see that your reef is vibrant and your fish are lively. You’d probably spare no expense to give your tank the best of the best, right?

As much as we want to invest in our tanks, sometimes money is a factor we have to consider. This filter is definitely an investment with it being priced at above the point of other tanks in its category.

This isn’t necessarily a bad thing if money is of no consequence, but for us average Joes on a budget, it may make or break your decision.

Be Careful with Small Fish

Powerful filters mean powerful suction, which doesn’t bode well for small fish.

The little swimmers run the risk of being sucked in, and you wouldn’t want to think about what happens after that.

Though this hasn’t been a major complaint with this filter, it’s always best to err on the side of caution.

When using this filter, make sure that your tiny guppies don’t run the risk of meeting their fate at the hands of something designed to help them.

Time Consuming

While the lid on the Fluval FX4 is made to be strong and tight, it can take a bit of extra time to take off and put on.

The cost of a very tight seal doesn’t make the task any harder but will take an extra minute or two to clamp down.

While this isn’t hours and hours of a delay, it can be annoying for those who want to get things done super quickly.

Overall Verdict

This filter is powerful, thorough, easy to use, and will have your water looking crystal clear in no time.

It’s the perfect option for beginners or professionals that want a clean tank without the hassle.

Though it is on the more expensive end, and you’ll have to take extra precautions to protect your smaller fish, you’ll find that the Fluval FX4 Canister Filter will more than make up for the price.

Where to Buy the Fluval FX4 Canister Filter

Fluval is already a popular brand in the aquatics market and the performance of the Fluval FX4 makes this filter no different. This canister filter isn’t hard to find in-stores or online.

To start, the Fluval FX4 Canister Filter can be found at the following online retailers:

And of course, it’s also available for purchase on Amazon.

fluval canister filter

That’s it for our review on the Fluval FX4 Canister Filter. Tempted to give it a run?

Fluval FX4 Canister Filter Rated
  • Quality of Filtration
  • Build Quality
  • Accessories
  • Ease of Use
  • Value for Money

FCG Verdict

By paying just a little bit more than most canister filters, you’ll be getting a product that lasts with the Fluval FX4 Canister Filter.

The filter’s power and ease of use go hand in hand to ensure your pets have crystal clear water for a long time.

>>> Check today’s price on Amazon.

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