Fluval FX6 Canister Filter by Hagen Reviewed: Still Number 1 in 2024?

The Fluval FX6 from Hagen claims to offer a simple, worry-free solution for high-performance filtering of tanks up to 400 gallons in volume.

Is the Fluval FX6 the best water filtration system for your aquarium? 

To find out, I purchased the FX6, ran it through some tests and took a closer look at this canister filter to see if it outperforms the competition and where it may fall short.

Overview of the Fluval FX6 High Performance Canister Filter

I think the Fluval FX6 canister filter is completely AMAZING. It did take me about an hour and half to read the instructions and get it set up, but I can’t believe how easy it is to use otherwise and especially to do maintenance on.

This filter is a total beast and really only suited to large tanks, so it may not be for beginning aquarists, but I​​ think it’s worth every penny if you want a big, heavily stocked tank.

I recommend it for aquariums that are 75-150 gallons (284-568 liters).

Shop For The Fluval FX6 Canister Filter On Amazon
Shop For The Fluval FX6 Canister Filter On Amazon

    Last update on 2024-03-04 / Commissions Earned / Images from Amazon Product Advertising API

    If your tank is too small for an FX6, but you still want a totally awesome canister filter, take a look at the Fluval 07 series.

    How I Tested & Reviewed The Fluval FX6 Canister Filter

    Fluval FX6 Canister filter boxed

    I wanted to get a solid handle on what it’s like to use an FX6 day in/day out to really get a true user experience.

    I was especially interested in looking at:

    • Installation – how difficult was it to get this filter set up?
    • Priming – is it difficult to get this filter started for the first time or after maintenance?
    • Performance – how well does this filter maintain water parameters? Does it do a good job of removing fish poop?
    • Maintenance – how difficult was it to do routine maintenance on this filer? 
    • Noise – how loud is the filter?

    Here’s an interesting fact, none of my regular aquariums are big enough for an FX6. My biggest tanks are 55 gallons (208 liters). You could definitely make an FX6 work on a 55 gallon, if your fish thrive in a high flow environment, like hillstream loaches

    But, my bigger tanks are dedicated to angelfish, and they DEFINITELY would be overwhelmed by the kind of current that an FX6 can produce.

    So, I had to get pretty creative on this one.

    I set up a 75 gallon (284 liter) horse trough with 20 comet goldfish out in my barn.

    Fluval fx6 testing

    Why goldfish you might ask? Because they are the dirtiest fish that produce more waste than just about any other species in the aquarium trade. 

    Plus, they’re cheap and widely available. I got mine from one of the big chain stores for a whopping 20¢ a piece.

    I got the FX6 set up, added seasoned filter media from one of my established tanks and added the goldfish.

    Then, I just treated this set up like I would any of my other aquariums: feeding the fish, doing water changes and overall enjoying the general fishiness of the fishes.

    Shop For The Fluval FX6 Canister Filter On Amazon
    Shop For The Fluval FX6 Canister Filter On Amazon

      Last update on 2024-03-04 / Commissions Earned / Images from Amazon Product Advertising API

      Fluval FX6 Canister Filter Reviewed

      Fluval fx6

      The Fluval FX6 is one of the most popular canister filters among aquarists thanks to its huge volume rating and flexibility.

      Let’s find out just how great this filter is.

      What’s in the Box?

      There’s quite a bit to unboxing one of these babies!

      • Fluval FX6 canister filter
      • Pump unit and power cord
      • Intake stem and output nozzle
      • Purge valve hosing
      • Suction cups and rubber feet
      • Rim connectors, clips, and lid fasteners
      • Utility valve and drain cap
      • Media baskets (3)
      • Bio-foam inserts (2)
      • Carbon filter pad
      • Media packs (2)
      • Instructional manual


      • Aquarium Capacity: 400 gallons (1,500 liters)
      • Filter Circulation: 563 gallons per hour (2,130 liters per hour)
      • Pump Output: 926 gallons per hour (3,500 liters per hour)
      • Wattage: 43 watts
      • Media Baskets: 3
      • Mechanical Area (Foam): 325.5 square inches
      • Biological Volume: 1.5 gallons (5.9 liters)
      • Filtration Volume: 5.28 gallons (20 liters)
      • Head Height: 10.8 feet (3.3 meters)
      • Warranty: 3 years

      So, here’s how the Fluval FX6 measured up during testing:

      Installation & Setting Up the Fluval FX6

      Honestly, installation is the only real drawback to this filter. Normally, I don’t even bother looking at the instructions on a fish filter. I just toss them over my shoulder, let the cat shred them and go along my merry way.

      But, not with this filter! I feel like I should get some sort of technical certification after reading the instructional manual. 

      OK, maybe that’s a bit of an exaggeration, but it is a pretty darn big instruction manual. I HIGHLY recommend that you read the ENTIRE manual before you start trying to do the actual installation.

      You’ll need to open up the canister and take out all of the media baskets. The ceramic biomedia and the activated carbon are in plastic bags that will need to be removed. 

      The biomedia most definitely needs a thorough rinsing. Mine had tons of dust and little particles that needed to be washed away.

      The stacking media baskets are really easy to take out. There are little red handles on either side that you can grab and pull out all of the baskets at once. With some filters, you have to fish around in the dirty filter water to be able to grab out media baskets, so being able to pull them out all at once from the top is great.

      The same handles that let you pull out the baskets also serve to hold all the baskets together. Once you’ve got them out, you just pop off the handles so you can separate the baskets.

      I love all of the huge, reusable mechanical filter media that comes with this filter. There are several different sponges, of different coarseness levels, throughout the baskets. In my opinion, there is no need to add disposable filter floss to this setup.

      You also get tons of ceramic noodles that make excellent biomedia. I added some seasoned ceramic pieces from one of my established tanks and just mixed them in with the new stuff to jumpstart the cycle. It worked really well.

      There are also really big mesh bags of activated carbon included. I personally don’t use carbon, unless I need to remove meds from the water column, but for all you diehard carbon fans out there, you get lots with this filter.

      The biggest drawback to setting up this filter is the hoses. There are two hose clamp/holders that bend the intake and output hoses around the edge of the tank. They’re very necessary, the hoses would not make the turn into the tank without them, and it would all be a big mess, but they are a serious pain to get set up. 

      You have to force the hose to fit the curve of the bottom piece of the holder and then clamp the top onto it. Let’s just say that I said some VERY unladylike words while I was trying to wrestle the hoses into these things.

      FX6 tubing

      I then said some things that are probably illegal in my state when I had to readjust them. 

      Once you get them seated, the clamps work great at keeping the hoses in place, it’s just a lot of work to get to that point.

      I would highly recommend that you allot at least an hour and a half, possibly two, to getting this set up. It’s not really hard, but it is fairly involved.


      Priming this filter could not possibly be easier. All you have to do is fill the canister with water, seal it up and plug it in. That’s it.

      No pumping a handle, begging and pleading with the water to move through the hoses or urges to bang your head against the wall. It just starts right up.

      Your FX6 may shut off shortly after you get it started. It does this so it can push out trapped air. It will usually shut itself for up to 10 minutes each day (I have never noticed it do this for more than about 3 minutes but the manual says 10) to burp air out of the system. Once the air is cleared, the pump will automatically start back up.


      GPH: 536

      OK I gotta be honest, I expected to have to deal with tons of poop and mulm in the bottom of the tank since goldfish put off so much waste. But this filter sucked up every single bit of it.

      Granted, this is a bare bottom setup, but I’m used to still having a bunch of gunk at the bottom of the tank that has to be vacuumed up, even in a bare bottom tank.

      But not with this FX6. The bottom has always been completely free of waste.

      The water has stayed crystal clear and the water parameters have been perfect since day one.

      I’d say this filter does its job and then some, big time!

      Maintenance: How To Clean Your Fluval FX6 Canister Filter

      I thought that having to break down this big canister to do maintenance was going to be a major pain, but I​​ was pleasantly surprised by how easy it was.

      There is a cool drain that you can open up at the bottom of the filter to let water out of the canister. You get a piece of clear tubing that you can attach to the drain that will let you pump the water into a bucket.

      You shut off the valves for the intake and output and then remove them. That lets air into the system and you then just attach the included tubing, open the drain and gravity will force the water out. So easy!

      Then, you just open up the canister and pull out the baskets. It only took me about a half hour to drain the canister, pull out the baskets, clean out the reusable sponges and put everything back together. 

      It really didn’t take me any longer to clean this huge filter out than it does to break down and clean out a hang-on-the-back filter. I was astounded. 

      Also, I really didn’t notice any sense of bypass. It looked like all of the different sponges were equally gunked up.

      You get a super nifty maintenance schedule that tells you how often to replace/maintain things like the o-ring seals.


      I have to say that this is a really quiet filter! I couldn’t believe it. It pumps out SO much water and all you hear is just a little hum. 

      I used a decibel meter so I could really quantify it. The meter showed exactly 50 decibels. 

      By comparison, the noise from the SunSun filter I also tested was 56.4. That might not seem like that much, but the decibel scale is logarithmic, so each decibel point you go up is 10 times louder than the point below it.

      So, the SunSun filter was 4 times louder than the FX6. The SunSun had a low buzzing, nothing at all loud, but it was still much more noticeable than the super quiet hum the FX6 produced.

      Shop For The Fluval FX6 Canister Filter On Amazon
      Shop For The Fluval FX6 Canister Filter On Amazon

        Last update on 2024-03-04 / Commissions Earned / Images from Amazon Product Advertising API

        Overall Pros & Cons

        Here’s a rundown of my pros & cons:

        FX6 Pros: 

        • GPH: 536
        • Amazing biomedia capacity
        • Effortless priming
        • Extremely quiet
        • Excellent instructional manual
        • Simple maintenance

        FX6 Cons: 

        • Plan on an hour or two for install
        • Canister requires a lot of space

        How Does it Compare?

        Definitely, the FX6 has the highest GPH and largest media capacity of all the canister filters I’ve tested. If you’re looking for something that can handle a huge tank and a lot of fish, I don’t know of another canister that’s in the same league as this one.

        This filter is also amazingly quiet; I measured only 50.0 decibels. It’s much quieter than the SunSun, which produced 56.4 decibels. The FX6 was even quieter than the much smaller  Fluval 407, which was almost 20 times louder at 51.9 decibels.

        Priming this filter was a breeze, especially compared to the SunSun. All I had to do was fill up the canister and plug it in. The filter started right up, burped out the air in the system on its own, and went right back to chugging away.

        Trying to get the SunSun to prime nearly robbed me of my sanity. Priming the FX6 was so much nicer.

        And none of the other canisters I looked at had the super cool drain thingy that lets you pump the water out of the body of the canister when you’re doing maintenance. You have to carry the canister full of dirty water to the sink with the rest.

        But, one drawback, the FX6 takes up a lot of room. Much more than any of the others. You’ll definitely need a plan for where you’re going to put this big beast.

        Verdict: Who is the Fluval FX6 Ideal For?

        I would say the Fluval FX6 is best for large, heavily stocked tanks. 

        This filter would be major overkill for a 40 gallon (151 liter) guppy tank, but if you’ve got a 100 gallon (379 liter) African cichlid tank, or something like it, this thing is perfect.

        It will help trap waste and keep your water nice and clear. And it’s got so much room for biomedia that it should be able to handle a ton of fish.

        So, great biomedia capacity, plus great mechanical filtration, all with an ultra-quiet but really powerful motor. That’s pretty damn perfect in my boat!

        I would recommend this filter for 75-150 gallon (284-568 liter) tanks. Make sure that your cabinet can accommodate the canister, since it’s quite large. 

        Overall, I can’t praise this filter enough. Fluval has really outdone themselves with this bad boy, really impressed. 

        I hope you find this article helpful.

        I wish you and your fish the very best!

        Shop For The Fluval FX6 Canister Filter On Amazon
        Shop For The Fluval FX6 Canister Filter On Amazon

          Last update on 2024-03-04 / Commissions Earned / Images from Amazon Product Advertising API

          Alternatives to the FX6

          Here are some alternative canister filters for you to take a look at:

          Fluval FX4 High Performance Canister Aquarium Filter - Multi-Stage Filtration, Built-In Powered Water Change System, and Basket-In-Basket Tray Design
          Fluval FX4 High Performance Canister Aquarium Filter - Multi-Stage Filtration, Built-In Powered Water Change System, and Basket-In-Basket Tray Design
            Hydor Professional External Canister Filter – Aquarium External Filter – Telescopic Intake Tubes, Easy Priming – EcoSystem in a Box – Biological, Mechanical, Chemical Filtration – 190 to 345 gph
            Hydor Professional External Canister Filter – Aquarium External Filter – Telescopic Intake Tubes, Easy Priming – EcoSystem in a Box – Biological, Mechanical, Chemical Filtration – 190 to 345 gph
              Ehm Fltr 2217 Classic Wm 264g
              Ehm Fltr 2217 Classic Wm 264g

                Last update on 2024-03-03 / Commissions Earned / Images from Amazon Product Advertising API

                Katherine Morgan
                Katherine Morgan

                Hey, there! I'm Katherine from Northwest Florida. An aquarium specialist, I've kept tanks for over two decades, enjoy experimenting with low-tech planted setups and an avid South American cichlid enthusiast.


                1. Thanks for a thorough review. It was helpful.
                  You probably want to correct your comments on sound levels though.. One Bel, which is ten decibels, is ten times as loud. Three decibels difference then is about twice as loud (10 raised to the power of 0.3). So a difference of 6.4 decibels would be 4.4 times as loud.

                2. Have used several FX6 for a number of years agree with all your comments re FX6 Just add that if initial output from filter is too strong turning the output valve to restrict flow is an option.

                3. My fx6 stop working for no reason at all had it about to years took at apart for maintenance lubricated the O rings a moving plastic parts came on but wouldn’t start. Re did it again same thing, change pellet about six months ago for same reason. Like the filter was about to order another.. Did I mention was at it for about two to three day tried one more thing never had done it before, happy to say I saved around $400 (I SELF PRIMED IT) Thank you very much!! Highly Recommend.

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