Fluval FX4 Review (Best Canister Filter for Up to 250Gallons)

Fluval FX4 Review (Best Canister Filter for Up to 250Gallons)

Fluval FX4 Review

Fluval FX4 Filter aquarium

Whenever it comes to the quality wise best filter Fluval brand is the top known among these. As the discussion comes to the filter, the user demands to get cheaper filter having a lot of features i.e. multi-functional filter.

The first thing that comes into mind is Fluval. Due to its features, this filter is very famous among users. And the most sold-out product is this.

The Fluval package comes with all accessories that a fish keeper can need. It is incredibly easy to set up. The package includes the following products in it:

  • Mechanical, chemical, and biological filter media
  • 2 stackable baskets
  • Multidirectional output nozzles
  • Rubber feet
  • Utility valve
  • Smart pump
  • Connection ports
  • Anti-clog strainer

Fluval FX4 Filter

Due to some specific features of Fluval fx4, it is very famous among its users. The features of this filter are as follows:

  1. Self-primer
  2. Utility valve
  3. Beautiful design
  4. Filter media
  5. Maintenance
  6. Silent worker


1- Self-primer

Fluval FX4 Versatile Design

One of the best features of Fluval fx4 is its self-priming. It will not just prime the tank itself but also decrease your burden too. With this fx4 you have to just fill up the tank with water. Turn the power on and it will start its working. The pump has the ability to readjust itself after every 12 hours. At the time of readjustment, it will make a loud noise. So, you will beware of this incident if it happens at an uncertain time.

If you are using a tank that has no self-priming feature, then this will definitely attract you. In the case of every self-priming tank, the alarm down not buzz. When the filter automatically turns on or off, make sure that the air fully emptied from the filter. This will remain for 2-3 minutes only, after this, it will normalize to its function.

2- Utility valve

Another beneficial feature of the Fluval fx4 is its purge valve.  You can attach Fluval Fx Gravel Vac to it but it will also help you in changing water. In case of replacement of water, simply you have to connect the purged hose to it and run into the yard or anywhere you want to release the spoiled water of the tank. But in case of refilling, you have to add water manually i.e. bucket by bucket. You cannot use this hose for adding water. It is necessary to add treated water. In case that adds untreated water then you have to treat the water with chlorine that may harm your beneficial bacteria too. To use this purged valve simply turn off the filter and after refilling you can start it again.

3- Beautiful Design

Fluval FX4 Dimensions

The Fluval fx4 has a beautiful and compact design. The exact dimensions of this filter are 15.6*15.6*17.7. so you can adjust it everywhere you want into small spaces and aquarium stands. It has a very unique style that every fish keeper attracts from it. If you have not fitted any filter into your cube, then Fluval fx4 is the best choice for you that will never disappoint you.


4- Filter media

Fluval FX4 Maintainance

The Fluval fx4 filter media works efficiently and does filtration 5 times in one round. At first mechanical filtration takes place. The water passes from the filter, the filter removes all sorts of solid debris.

It is recommended to do chemical filtration at the last because putting it to the end will last for a long time and it needs to be changed with time.

After this, the water passes from biological media means the biological filtration takes place here. At the last chemical, filtration takes place. For this purpose, you can also add ammonia or any chemical of your own choice at the bottom.

When you bought the filter for your home, you will notice that there is enough space for filter media in it. You can add filter media into it of your own choice. I would always recommend bio max media for the aquarium. You can also add ammonia or water polish into it.

5- Maintenance

Fluval FX4 Maintainance Technology


It is very easy to maintain and clean the Fluval fx4. To open the filter you have to unscrew the 8 screw clamps and the lid will open. Once the lid is open, pull the two red levers apart from filter baskets then you will easily replace or change the filter. In case to get to the pump, you have to remove three screws. You will reach the pump.

Keep in mind don’t lose the sealing ring.

The filter also consists of a dial that will remind you that when your filter needs to be changed, cleaned, or repair.

6- Silent worker

The filter does not produce any sound. It is quite enough that no will notice its working at your home. It will only produce a sound when it will clean itself from the air. After every 12 hours, it will perform the same job. So in this case most of the sound will come from your tank not from your filter.

Fluval FX4 Vs FX6: What’s interesting in it?

Fluval FX4 Vs FX6

Pros and cons

  • Beautiful design
  • Self-maintenance
  • Noise-free
  • Mechanical, chemical, and biological filtration
  • Self-priming
  • Anti-clog strainer

  • Expensive
  • Removing the lid take time
  • Hose clips were not sized properly


Hence, Fluval fx4 is the beast. It does a much better job than any other filter. So, this deal is not bad for a fish keeper, for the love and care of its fish. It has brilliant features and working is also awesome.

Flora is a Fish Parent & Enthusiast for over 10 Years. She has Deep Love & Affection for Fish Keeping. It's become her Passion to Help others. Stay Tuned with her Blog to Know more about Pet Care Tips, Product Reviews, and Guides. If you've anything Interesting to Share about your Fish. She'd Love to Know.