Are Fluval Filters Good? (We put them to the test!)

The number of filters available on the market today is crazy. Sponge filters, undergravel filters, internal filters, hang on back filters and canister filters, the choice is endless. It can be difficult to know which one to go for. Fluval is one of the most well-known manufacturers on the market today. One question I am asked on a regular basis is…

Fluval has been making filters for over 30 years. They make a wide selection of filters and are considered to be one of the best filter manufacturers in the world. Their external filters are of excellent quality and are probably the most widely sold external filter in the USA.

Fluval currently has 22 different filters on the market. They have designed and built filters for every tank from a 15 gal nano tank to 400-gallon mega tanks. Whether you want an internal, external, or hang-on-back filter, Fluval has one for you.

I currently use a Fluval 407, an FX4, an FX6, a C3, and a C4 filter. I have to say I have been really impressed with the filters and I wouldn’t hesitate to recommend them to others.



The Fluval Filter Range

NameTypeGallonsPowerFlow RateWarranty
NanoInternalUp to 15 US Gal6.8w81 gal/ph2 Years
U1InternalUp to 15 US Gal4.5w65 gal/ph3 Years
U2InternalUp to 30 US Gal5w105 gal/ph3 Years
U3InternalUp to 40 US Gal7.5w155 gal/ph3 Years
U4InternalUp to 65 US Gal10w260 gal/ph3 Years
C2Hang-on-backUp to 30 US Gal5w106 gal/ph2 Years
C3Hang-on-backUp to 50 US Gal5w127 gal/ph2 Years
C4Hang-on-backUp to 70 US Gal5w238 gal/ph2 Years
107CanisterUp to 30 US Gal10w95 gal/phup to 5 Years
207CanisterUp to 45 US Gal10w121 gal/phup to 5 Years
307CanisterUp to 70 US Gal15w206 gal/phup to 5 Years
407CanisterUp to 100 US Gal20w245 gal/phup to 5 Years
FX4CanisterUp to 250 US Gal30w450 gal/ph3 Years
FX6CanisterUp to 400 US Gal41w563 gal/ph3 Years
G3CanisterUp to 80 US Gal17w185 gal/ph2 Years
G6CanisterUp to 160 US Gal28w265 gal/ph2 Years

Fluval Nano Filter

The Fluval Nano has been designed by Fluval for the smallest aquariums. They recommend it for use in aquariums up to 15 gallons and the flow rate can be turned down so it can be used in smaller tanks too.

The Fluval Nano works by drawing water in and through a fine sponge, which offers both mechanical and biological filtration. Fluval also produces a carbon cartridge, which they sell separately. The carbon cartridge helps remove bad odors and other impurities from your nano aquarium.

This filter comes with an optional spray bar. The spray bar, combined with the variable flow, makes this filter suitable even for nano aquariums with delicate fish or shrimp.

This little filter turns water over at a rate of up to 81 gallons per hour, which is more than sufficient for a nano tank.

Fluval offer a 2 year warranty on their nano filter, and they sell a number of spare parts, should you need to replace them outside the warranty period. Although Fluval recommends replacing the sponges on a regular basis, there is no real need to replace the sponge until it starts to fall apart, which will probably be after many years of use. In fact, if you bin the sponge and replace it with a new one, you also bin all of the beneficial bacteria living on that sponge!


Fluval ‘U’ Series Of Filters

The ‘U’ series of filters are Fluvals range of internal power filters. U1 has been designed for aquariums up to 15 US gallon, whilst the U2 is for aquariums up to 30 US gallons. The U3 internal filter has been made for tanks up to 40 US gallons and the U4 for up to 65 US gallons.

Unusually for internal power filters, the U2, U3 and U4 filters boast a 3 stage filtration system. The water is drawn in through a sponge, which provides mechanical filtration, physically removing floating dirt and detritus from the water column.

Next the water passes through a poly-carbon pad which removes the finest particles from the water whilst also neutralising odours and helping clarify the water. The final stage of filtration sees the water passing through a chamber filled with Fluval Biomax filter media. The Biomax provides an ideal home for beneficial bacteria, which break down the waste from the fish, which is naturally high in ammonia.

Another feature that is rarely seen in an internal aquarium filter is a 3-way flow system built into the U2, U3 and U4. This system allows the water flowing out of the filter to come out either directly through the traditional top output, or a central spray bar located vertically up the middle of the filter, or via another output located at the base of the filter.

The ‘U’ series filters can be placed in the aquarium either vertically, or horizontally. This ability to lay on their sides makes the ‘U’ series of filters ideal for terrariums and turtle tanks.

Fluval have designed the ‘U’ series filters to be easy to service. The U2, U3 and U4 filters all have a quick, flip top opening lid, providing easy access to the filter media chamber for cleaning and servicing the filter.

To clean your Fluval ‘U’ series filters, simply unclip the flip top lid, carefully remove the filter foam/s, the poly-carbon cartridges and Biomax biological media chamber and rinse everything in water that has been removed from the aquarium. Never rinse the filter media in tap water as the chlorine will kill the beneficial bacteria in your fiter. After cleaning, replace everything back into the filter and switch back on.

The ‘U’ series of filters come with a generous 3 year warranty, giving you peace of mind that they are built to last.


Fluval ‘C’ Series Of Filters

The ‘C’ series of filters are Fluvals range of hang on the back filters. ‘C’ stands for ‘Clip-on’. This range comes in 3 different sizes for aquariums which are up to 30 US gallons, 50 US gallons and 70 US gallons. The ‘C’ series offers users a 5 stage filtration process which Fluval claims ‘combines the best features of a canister filter with the ease of a hang-on filter‘.

According to Fluval, the 5 stage filtration system offers both easy replacement of media and customization to suit any setup. ‘C’ series filters are suitable for both freshwater and marine aquariums.

The intake tube extends to offer the user flexibility in how deep to draw water from. Water is taken up through the intake tube, which includes a fitted strainer, preventing small fish or larger pieces of debris being sucked into the filter. Once drawn into the filter, the water passes firstly through a coarse foam, then a denser poly layer which filters out finer debris.

Next the water travels through a sachet of activated carbon, which removes impurities from the water. Once exhausted, this sachet of carbon can be replaced with any, suitable, bagged media. The fourth stage of filtration sees the water pass through a Bio-Screen block which prevents debris from passing into the final chamber.

The last chamber, stage 5 of the filtration process, contains biological media, designed to quickly reduce toxins such as ammonia and nitrite in the aquarium water.

Fluval have designed their ‘C’ series of hang on back filters to be easy to maintain too. There is a small pop-up indicator when the filter needs servicing. When the indicator pops up, simply remove the poly pad/foam and rinse in a bucket of water taken from the aquarium.

The section containing both the mechanical foam and the chemical basket are easily removed for cleaning and maintenance.

One question I am often asked about Fluval filters is ‘when should you change the carbon?’. The answer is, it depends on a number of factors including, how heavily stocked your tank is and how much water your filter is processing.

If you notice your water has a slightly yellow/brown tint to it, or there is a bit of a ‘fishy’ smell coming from the water, consider replacing the carbon.

Another question I get a lot is ‘should I change the foam in my filter’. Despite what Fluval says, you should only ever change your sponges if they are physically falling apart or have become so clogged you can no longer clean them. If you dispose of the sponges every month as suggested, you also dispose of all the good bacteria living on the sponge. With the exception of fine filter wool, which is designed to be disposable, I’m not sure I have ever thrown any filter media away, ever!



Fluval 07 Series

The Fluval 07 series of filters marks the 7th incarnation of an external filter Fluval have made over the last 40 years. According to Fluvals testing, the 07 series of filters are up to 25% quieter than previous models. Fluval say their 07 series are more robust, more energy-efficient and offer the user more flexibility than any filter they have produced before.

These filters, which are built in Italy, combine clever engineering like a diamond polished impeller shaft, which is said to be 50% smoother, with simple, but effective upgrades like rubber feet to damped noise and reduce vibrations.

Fluvals 07 series of filters have powerful pumps (the 407 can pump water to a height of almost 7ft) yet run on as little energy as a light bulb (just 10w from the 107). According to Fluval, you can run a 107 fitler from as little as $17.52 a year.

This range of external filters offer four new design refinements, each of which has been designed to make the aquarists’ life a little easier.

  • The ‘Aquastop valve’ has a new ergonomic design and a slightly raised lip for soother operation. Being able to shut off the water draining from the aquarium and disconnecting the hoses easily, and with little mess, is a feature anyone who has used a canister filter in the past will appreciate.
  • The ‘Lift-Lock Motor Head Clamps’ allow you to unlock the pump in a single action. The 07 range only uses two clamps to secure the motor head, whereas many competitor canisters have 4 clamps.
  • Fluvals ‘EZ-Lift Media Baskets’ make removing the media from the canister quicker and less messy. You can now remove the media without having to take the water out of the canister.
  • The redesigned ‘Quick Primer’ requires less time to prime the canister than the old system did. Fluval have also strengthened the primer handle, reducing the chances of it snapping during priming. The 07 series primer handle has been designed for just 2 finger operation.

Another major benefit of the 07 series is the customizability of the filtration system. Fluval currently offers 13 different types of filter media that can be used in almost any combination.

For pre-filtering, the 07 series utilizes foam with a rippled surface which offers up to 30% more surface area than using a conventional flat foam piece. Next, a layer of Bio-Foam traps finer particles of waste and debris. The cleaner the water is before it hits the biological filtration baskets, the more efficient your filter will be.

Following pre-filtering, the 07 series boasts 3 baskets for filter media. It is in these 3 baskets where the real customization becomes possible. You can use almost any combination of the following media;

  • Bio-Foam+: Boosts beneficial bacteria growth
  • Bio Max: Provides an ideal home for beneficial bacteria
  • Carbon: Removes harmful toxins and odors from the aquarium water
  • Ammonia Removal: To neutralize toxic ammonia that will kill your fish
  • Zeo-Carb: Removes toxins, ammonia and odors from the water
  • Peat Granules: Peat granules can be used to naturally acidify the aquarium water
  • Phosphate Removal Pad: Removes excess phosphate which can cause algae issues
  • Nitrite Removal Pad: Can be used to remove nitrites
  • Ammonia Removal Pad: Can be used to remove excess Ammonia from the water column
  • Quick Clear Pad: Use to ‘polish’ your aquarium water for a crystal clear tank
  • Pre-Filter Media: Can be used to trap sediment before passing through any of the options above

It is the ability to really modify your 07 series filter to fit your individual aquarium needs that makes this series of filters so useful to the home aquarist.


FX Series Of Filters

The FX series of filters are Fluvals ‘Big Boys’. Big filters for filtering big tanks! The FX4 will filter aquariums up to 250 US gallons and the FX6 will filter aquariums up to 400 US gallons. These filters have been designed to deal with heavy waste loads. Fluval knows that large tanks often mean large fish, which nearly always means large waste loads.

These filters boast powerful pumps, multi-stage filtration and a built-in, easy water change system. The ethos behind the FX filters appears to be less time maintaining your filter, more time enjoying your fish. Fluval say their FX filters have been designed to ‘sweep the tank harder and faster’.

This method of filtration means more debris is removed from the water column and held in the filter, reducing the amount of in tank maintenance required.

Multi-Stage Filtration

The FX4 offers a 4 stage filtration system. This filter has 2 large baskets, both of which have a smaller basket inside. As standard, the FX4 comes with 4 pieces of foam, 1 piece of Bio-foam, 2 bags of Bio-Max, 1 carbon foam and an additional media bag to allow for customization.

The FX6 has a 6 stage filtration system. The FX6 has 3 baskets, 2 of which have an inner basket as well. This filter comes with 6 pieces of foam, 2 pieces of Bio-foam, 2 bags of Bio-Max filter media, 1 carbon foam and an additional filter media bag.

One major feature of the FX range of filters is the ability to change water directly from the canister filter. The FX filters have an outlet at the bottom of the canister where you can attach a hose. Once a hose is attached and run to a suitable drain, simply turn the tap and the water runs from the aquarium. Once sufficient water has been drained, fresh, dechlorinated water can then be returned via the same hose and pumped back to the aquarium.

An additional piece of equipment you can source for your FX filter is a gravel vac. This gravel vac connects to your FX filter via the utility tap at the bottom of the canister. A thumb operated control valve allows pressure to be regulated whilst vacuuming the substrate.



G Series Of Filters

In their ‘G’ series of filters, Fluval brings together advanced filtration and cutting edge technology. The G3 and G6 filters have been designed to filter 80 and 160 US gallons respectively. This range of filters offer a 3 stage filtration process and they are designed for use in freshwater and marine setups alike.

The G3 and G6 filters both have a digital display which, through internal sensors, displays the aquarium temperature, the filter flow rate and advises when maintenance is due.

The media cartridges inside the G series filters are designed to be easily removed for maintenance. The top of the filter opens up, allowing the aquarist to pull the cartridges out.

Additional features of the G series of filters include quick disconnect hoses, easy prime button for starting filter without manual siphoning, silicone gaskets for superior sealing a double wall construction to reduce noise from the motor.

In Conclusion

Are Fluval filters good? Fluval filters are some of the best aquarium filters on the market. It is fair to say they aren’t perfect, but the ability to customize so many of the models means there is a Fluval filter to fit almost every aquarium set up.

I have personally had great success with their canister filters and I would certainly recommend them to a friend who was looking to get into fish keeping. The FX6 in particular is an excellent filter for large, messy fish like Oscars, African Cichlids and Goldfish.


About the Author

I’ve been keeping, breeding, and showing tropical fish for nearly 30 years. Over that time I’ve done it all! I’ve had great success and I’ve made some really foolish mistakes (like the time I bought an Asain Walking Catfish). Read more…
Richard James
Editor