Fluval FX6 Review

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Fluval Fx6 Filter Review

The Fluval FX6 by Hagen promises to be a hassle-free, high-performance filtration solution for tanks up to 400 gallons in volume. When it comes to canister filters, the Fluval FX6 is the best of the best, whether you’re talking to a fishkeeper who’s been around long enough or a person that’s just tried it once. 

This filter has been on the shortlist for best canister filters on the market and built quite a reputation for itself since its predecessors have been dominating the market for years. 

This model comes with quite a beefy price tag, but it sure justifies itself by not only the unmatched quality it provides but also the simplicity behind it, from setting it up to using it for years. It’s a filter with different qualities that can make even the pickiest people fall in love with it and what it gives.

TypeExternal / Canister filter
Aquarium CapacityUp to 400 Gallons
Suitable forAquariums
Filter Circulation563 GPH
Filtration TypeMulti-stage Filter
Biological Volume1.5 gallons
Mechanical Area325.5 in2
Pump Output925 GPH
Filter media includedMechanical, chemical, and biological
Head height10.8 feet
Size15.75 x 15.75 x 20.8"
ExtrasSmart Pump Technology for
optimum filter performance,
efficiency, and management

Fluval FX6 Overview

Because of its large volume capacity and versatility, the Fluval FX6 is one of the most popular canister filters among aquarists. The filtration system is enough to capture the attention of many enthusiasts with its design for tanks with a capacity of up to 400 gallons (1,500 liters). It can be modified to accommodate most tank shapes and sizes due to the filter’s extensible intake tube.

Fluval Fx6 Canister Filter Box

But it’s how simple it is to obtain high-performance filtering with this canister filter that genuinely sets it apart. All you have to do to begin filtration is plug it in since the pump is self-priming. Ensuring that a high-efficiency vacuum is always maintained, every 12 hours, the pump evacuates any trapped air in the system.

As for the filtering itself, this one uses 3-stage filtering combining all chemical, biological, and mechanical filtration. There’s a set of filter media that’s customizable and can be changed depending on how you want your water to be. This media comes pre-loaded in the canister, and it’s more than fitting for your primary tank.

What’s Included In The Package?

Besides the filter itself, the box comes with several items that otherwise you’d have to purchase separately.

  • Canister filter Fluval FX6
  • Pump and electrical cable
  • The stem of the intake and the nozzle of the output
  • Hosing for the purge valve
  • Rubber feet and suction cups
  • Clips, rim connections, and lid fasteners
  • Drain cap and utility valve
  • Three baskets for media
  • Two inserts made of bio-foam
  • Filter pad with carbon
  • Two packs of media
Fluval Fx6 Canister Filter Unboxing

How to Set Up Fluval FX6

Setting this bad boy up happens just like every other filter out there by assembling whatever media you need and adjusting everything to fit your aquarium. The first thing to keep in mind is the placement. You need to put the canister filter right underneath the tank for optimal usage and begin to adjust the intake and output assemblies. 

They can be connected by click-fit connectors and also put in place by the locking clamps that come in the box. After that, reaching from the canister, you should lay out the nozzles of input and output and cut the latter to extend to one inch below the waterline on your tank. 

Fluval Fx6 Setting up

The intake tubing should also be cut at around 6 inches below the top of the aquarium and the stem at approximately 1 inch below the water surface. Connect the multi-directional output nozzle to the end of the tubing with a locking clamp, and the most part is done. 

All that’s left is to fill the media baskets avoiding leaks, by leaving some space on top of each. Put the baskets in the canister after restacking them and hand tighten the fasteners to lock down the filter’s lid. 

We put a lot of emphasis on simplicity of use in our evaluation, so aside from the Fluval FX6’s sheer performance, the setup procedure is an excellent illustration of how this filter excels in either way.

Fluval FX6 vs. FX4

If you want a high-performing filter for large fish tanks, you’ll have to choose between the Fluval FX4 and Fluval FX6 because the Fluval FX5 is no longer available.

The Fluval FX4 is suitable for aquariums with a capacity of 100 to 250 gallons and accommodates the standard tank easily. However, the Fluval FX6 offers more excellent filtration and quicker water flow. If you want to keep fish that require a lot of flow and/or plan to overstock your tank, the Fluval FX6 for aquariums between 100 and 250 gallons would be the most logical choice. 

Fluval Fx6 Vs Fluval Fx4

For larger tanks, it’s no doubt that the Fluval FX6 has the upper hand, and as for smaller tanks, both could be used as they are. Unless you have fish who prefer a low flow rate, you’d need to adjust the water flow by yourself. For even smaller tanks, a strong filter isn’t necessary at all, so either of the FX’s wouldn’t be a wise choice. 

As for the Fluval FX5, the company discontinued the filter after it had a problem with buildup so that we won’t be addressing it in this article.

As you might’ve guessed, the Fluval FX6 is a bigger and slightly more powerful version of the other. Most of the specs on the Fluval FX4 are just upped with the Fluval FX6. This essentially means that your decision has to be made on what you need rather than who’s the best since it isn’t exactly a fair comparison if one is for more giant tanks and the other for smaller ones. 

If you need high power, strong filters, and good build quality, you’re sure to find it on both. Suppose you need the extra jazz though the Fluval FX6 will be the way to go. The price difference isn’t that big either, so if you’ve set your mind to get a Fluval FX series, the price between the models won’t be a deciding factor. 

Besides these, they all have the same components and work essentially the same. You might find the Fluval FX6 to be more popular because, as we said, there’s no such thing as too much filtering and people tend to go for the one that does the most when the price doesn’t really fluctuate. 

Our advice is that if the Fluval FX4 does the job, use the bucks to get yourself some decorations instead. However, if you plan on overstocking your tank or getting a larger tank, the Fluval FX6 is an excellent investment that will pay off in the years to come. 

Even if eventually you downgrade or upgrade to another tank, you’ll be safe with the Fluval FX6 since it works great on all medium to large sizes of tanks.

Features & Benefits of Fluval FX6

The Fluval FX6 canister filter is not the cheapest out there for sure. However, with an overwhelming list of benefits, the price tag is almost forgotten. Read below to learn more about the Fluval FX6 filter.

The Canister

The canister itself is the first subject worth discussing. You wouldn’t want to buy this filter just to find out it won’t fit your tank or doesn’t have enough media. The canister is 22 inches tall, so if you have an aquarium stand, it should fit inside most of the time, and it will also fit more media baskets than a standard-length canister. 

Fluval Fx6 Canister Filter Review

On the exterior of each basket will be foam that will function as mechanical filtration, which eliminates the big debris before it reaches the biological and chemical media.

After passing through the foam, the water will pass through the biological media and finally the chemical media. Remember that the filter media will last longer when maintaining the chemical media at the bottom of the filter if you intend on adding new filter media.

Works With Up To 400-Gallon Tanks

The Fluval FX6’s robust pump technology provides 538 US gallons per hour of filter circulation and 925 US gallons per hour of the pump output. In the aquarium hobby, there is a rule of thumb that filtration should be 6x the total water capacity of the tank. 

However, the Fluval FX6 offers a competitive advantage in serving even bigger tanks since it features a very effective filtering system. The Fluval FX6 will be more than plenty if you have a large aquarium or a medium-sized one. After all, you can’t over-filter your water, and there’s nothing to compromise either way.

Less Noise when Working

The Fluval FX6 doesn’t just do an excellent job at filtering; it’s also silent while at it. It’s so quiet that even to notice it, you have to be pretty close. It achieves this by using fewer mechanical joints on unidirectional impellers, making it the perfect choice for anyone who gets annoyed at different noises. 

Fluval Fx6 Review

It also produces fewer vibrations than conventional canisters and is really silent due to rubber feet that help decrease vibrations. Vibration is a typical issue with external canister filters, which is not only an obnoxious noise but is also harmful to your fish.

The Fluval FX6 canister filter, on the other hand, was designed to keep everything silent and still, which is excellent news to your fish, your tank as well as yourself.

Smart System

In this incredible piece of craftsmanship, there’s also something called a smart system. In essence, the filter has an electrical circuit board that constantly checks the impeller and ensures that it is operating at its best. This is amazing for anyone who simply wants to plug it in, let it operate, and not worry about it throughout the day.

Adjustable Water Flow

Staying with the Aqua Stop Valves may be used to regulate the flow and stop the water from flowing entirely. Change the flow rate by turning them to a smaller degree rather than 90 degrees. If you’re using the Fluval FX6 filter on an aquarium with a capacity of fewer than 400 gallons, this is a particularly useful feature.

Multiple-Directional Output

The Fluval FX6 filter also has different settings based on your aquarium’s and fish’s demands achieved by dual output nozzles. This means you can also ensure that filtered water is released in all regions in addition to directing the current where it is needed most in your aquarium to keep it clean.

Common Fluval FX6 Problems and Solutions

Like every other product, this one has its flaws and can most often be solved in a pinch. There’s a pattern of misconceptions and problems that usually happen with this product, and you’ll find them explained below.

Startup Issues

One of the most typical issues with the Fluval FX6 filter is that it would not start after cleaning. There are various reasons why the Fluval FX6 won’t start, and the most common is that the impeller has become stuck. 

The interior should be cleaned and rinsed. To remove any trapped sand or debris, remove all of the filter material and baskets, then thoroughly clean the basket and impeller. After that, rebuild everything and try again. 

The other option is if the media is trapped in the pump. Remove any material that is trapped or clogging the pump by opening it and removing it. After that, rebuild everything and try again.

Noise Issues

We mentioned earlier that this filter is one of the quietest out there, but that doesn’t mean anything will ever happen that might affect that. Different things can happen, like debris being stuck on the impeller or in the canister.

To solve the debris problem, either clean or replace the impeller or clean the entire canister system if the problem lies on the canister. 

Another problem might be the air might also be stuck in the canister, or its source might be too close. If it’s stuck, remove some media purge the Fluval FX6. If the source is too close, keep the sources away from each other or create barriers between the source and intake.

Flow Rate Issues

You may not be receiving the required flow rate or find that your Fluval FX6 has low flow after setup. Here are a few possible causes for this, as well as a remedy.

You’ve used too much media — Reduce the amount of media you’re using to ensure that water can flow freely through the canister. It’s possible that your impeller is stuck — Remove the impeller and clean it. Your hose might be clogged or obstructed; make sure all the hoses are debris-free.

Microbubbles, Popping & Excessive Bubbling

The Fluval FX6 filters tend to suck up air bubbles from air stones, other aquarium filters, and protein skimmers in the process since the filters are extremely powerful. Causes for that tend to either come through using too much media, having the intake too close, or if you’ve just set it up, it’s going to take some time to self-purge. Wait for at least 48h before jumping to conclusions.

Fluval Fx6 Canister Filter Cleaning


Cleaning this filter up can be done in 7 steps.

  1. Turn the levers on the aqua stop valves on the intake and output tubes 90 degrees to close them. Then disconnect the device from the power source.
  2. To discharge any remaining water in the canister, place a bucket under the purge valve and open it. When the canister is empty, transfer it to a more convenient location for cleaning.
  3. Using the red T-handle, release the media baskets from the canister, remove them, and adjust them.
  4. Clean the pump by removing the impeller and rinsing it in clean water.
  5. Reassemble the canister and reinstall the media baskets in the sequence in which you want them to connect to the water.
  6. Reconnect the hoses and reopen the aqua stop valves after closing the lid.
  7. Finally, reconnect the unit to the power socket and wait for it to self-prime. Check for leaks after a few minutes, just like you would with the initial setup.

Conclusion: Should You go for Another Alternative?

This filter is on the list for the best aquarium filter we’ve seen, and it shows that from the way it works and the minimal problems that arise during usage. This one would’ve been almost perfect if it came at a lower price, for this price tag might be a bit too much for some people. Either way, good filtration systems always cost the extra buck to provide that outstanding quality that we seek. 

If you’re looking for a more affordable option, we’d suggest AquaClear Filter. It’s got incredible value for money, and it’s likely to cater to the preferences of people looking at the Fluval FX6. Either way, this review is the perfect example of how a product with an intimidating price tag can justify it easily and even exceed expectations.

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I am Mario, a experienced fish keepr and the editor-in-chief of Epic Aquarium.

At Epic Aquarium, we take our commitment to providing comprehensive and unbiased reviews very seriously. Our team carefully reviews each product, and we only recommend the very best in terms of quality. We also consult with leading fish keeper experts to ensure that each article is based on the most reliable and up-to-date information available.

Disclosure: EpicAquarium.com participates in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for publishers to earn fees by linking to Amazon.com and affiliated sites.