Any filter with the name Fluval is always something to like whenever you see one. It is expected that you will end up with the right filter for your aquarium whenever you get a filter from Fluval.
Well, does the Fluval 406 external filter live up to the expectations of most people?
Comparing it to the previous models, we expect that it will have better features that would make it stand out. It does not disappoint if you have a sneak peak of the features.
You get a powerful motor and additional reliability you would want in an aquarium. Let us check more features you can expect from this model.

Table of Contents
Fluval External Filter 406 Review
Durability
The filter is expected to be used for a long time, so getting a strong and study filter would be important. The 406 model from its initial glance at its body, it is easy to see that it comes with a strong build on the outside.
What about the insider? Well, there is nothing to worry about as the interior is built to match the outside durability too.
Having the square shape design makes this model handle more water as compared to the normal round canister filters. Such a feature is a nice addition for those looking to have more water flow within a short time.
The design also helps with maximizing the contact of your filtration media with the water from the aquarium. Such activity should boost better filtration of the water.
Setting Up
Setting up a canister filter for most people is not a problem, but the newbies to these filters might have some doubts. Well, the doubts would be put to rest when you get the 406 model delivered to you.
The setup process for this model is quite simple and you will be done with the installation in no time.
The instructions, on the other hand, might not be that easy to understand, but if you put it together following the images, it should be done in less time.
Flow Rate and Capacity
The 406 filter is designed to have a bottom-top filtration process. The aquarium water will go through the inlet, past the filtration media, and then come out on the other side of the filter.
The question you might be having right now is just how efficient is this type of method. You can be sure that it will get the job done effectively and still within a short time.
To help improve the flow rate, the filter is designed with a hydraulic motor that increases the rate of filtration and reduces the maintenance the filter will need in the end.
The 406 model has the AquaStop valve, which is an upgrade from the other models, which lacked it. The valve is important to help in maintenance without really having to disconnect the main supply pipe.
When it comes to capacity, the model is made to be ideal for tanks up to 100 gallons.
Noise Level
Noisy aquarium filters are no one’s favorite and that is not going to change anytime soon. You are in luck if you end up buying the 406 model.
It will deliver a noiseless working environment that you can enjoy too if you are in the same room as the aquarium.
The manufacturer had to set it apart from its competitors by making it different. The noise level is quite reduced thanks to the sound-dampening design you get with the model. Such a design makes it quieter to up 15 percent than its closest competitor.
Filtration Media
This is where the bulk of the work is done. The water from the aquarium has to go through the filtration media and end up with clean water at the end. Having the square design helps a lot in the distribution of water for better filtration efficiency.
The filtration media in this model include a coarse sponge and additional 3 media basket. In the basket, you get the chemical, bio, and mechanical media for filtration.
Because of such impressive filtration media, the system would be perfect for the messy fish such as goldfish, cichlids, and still turtles in some cases.
Pros
- The quiet operation is attractive to many users
- The AquaStop valve helps with easy water control
- It comes with an effective priming technique
- It has a solid built due to high-quality materials
Cons
- The impeller tends to develop issues after about 6 months
- It can start to leak after using for several months
Verdict
Despite having a few issues here and there, it is a great model to handle your large aquariums. The overall design keeps the product sturdy meaning that you have an easy time knowing it will last you for longer. If you like it, then go ahead and get one for your aquarium today.
Have you guys fix the leaking issue?
Nope…
I was wondering if anyone could help at all. We have the Fluval 406 that we use with our 250 litre fish tank. It doesn’t seem to be working and is making a rattling noise. We have tried cleaning it but can’t seem to fix the problem, does anyone have any idea what we might need to do? Thanks in advance
if sounds like its ratteling you no doubt have air still inside canister. empty the canister and then fit back to tank and allow it to fill before powering on make sure both pipes are submerged once you see bubbles stop then plug filter in should all work fine. if not maybe faulty impeller
I had the same problem. It was a faulty impeller. Once I changed the impeller (bought on Amazon) it started working like a charm.
I have 3 FX 6’s. What a great filter. Multiple top clamps makes leaks very rare. Occasionally the thumb clamp must be replaced as the plastic nut cracks. New replacements are low cost but a nylon nut would be sturdier. After a year and a half I started to have a weak motor. Easy to replace for $80. The air purging and auto siphon are great as well as the water change mechanism. Love the filter. I need a FX2. The 206, 306, 406 have cavitation problems. FX is the way to the future!
My 2 year old Fluval 406 is leaking from the side , I replace the new O-ring, new impeller kit, all are genuine parts and it does not fix the leak. The media for this filter is great, but the material it is not durable. I am disappointed with Fluval products.
Glad I read this, now I’m going to buy a 406! If you could buy another , which one would u buy?
eheim classic
Ongoing leaking problems with both the 405 and 406. I have spent a lot of money on new units over 9 years of having the Fluval Venenzia, 77-gallon, corner bow front tank. I have replaced the O-rings, read through all the instructions and have become so frustrated, I am just going to give the entire system and hobby up. Can’t even go on a vacation and not worry if the power should go out, that I will return to a mess and water damage to my home. I have it working now to where it does not leak. However, if there is a power disruption and canister fills completely up, it leaks. Fluval (Rolf Hagen) not much help and can’t admit to having an inferior product.
my 406 always kicks out the impeller cover any time there is power outage and motor gets hot , will not start pumping on it’s own after power outage.
try lubricating the seal ring with silicone grease. https://youtu.be/BjqPuwMb7nc
Rolf is no help at all. Twice now after a power outage I have had to clean up a huge mess from my 406 filter. They are junk, crappy hoses that collect crap and they leak. I threw my 406 in the dumpster and purchased a new brand. We will see.
I have had the Fluval 406 for three months to filter a 4ft tank containing African cichlids. The filter itself works well however I have just replaced the black ribbed flexible hose which is supplied with the filter as within a couple of weeks setting the tank up I noticed each time I turned the filter on after cleaning I would get sediment shooting out of the hose into the tank. When I eventually took the hoses off I was amazed at how much sediment was trapped in the hose.
I replaced the hoses using a green transparent hose which enables me to see whats inside the hose and as the inner walls of the hose are smooth I am not getting trapped sediment shooting out of the tube after cleaning like I did with the Fluval supplied tube..
Ordered and paid for a 406 recently. Used a 5 tray dophin untill then. After reading PLENTY of bad reviews and complaints i was quite worried but it was too late to turn back.
Long story short, the filter arrived, well packed. It took me 15 minutes to cut and install the hoses and about 10 minutes to pack the trays and assemble the rest. Connected it, 2 or 3 pumps and i could hear water running into canister. Plugged it in and it started up immediately!
Super quiet and very strong flow. 2 days and my tank was cristal clear!
Everyone complaining about the ribbed tubing. I find it much easier to work with than my previous clear tubing and i did install a JBL inline diffuser as well. Everyone complaining about gunk building up inside the ribbed tubing…. I had exactly the same thing previously on smooth clear tubing so live with it. Also no leaks from the start. Maybe its because i pushed down on the top so firm that the clips did absolutely no “pulling down” its actually sitting in place witj the clips very lightly engaged.
Im a happy chappy and quite surprised about all the negative reviews. I wonder how many of those were due to human error?
5 stars from me, will buy another.
The ribbed hoses are the worst design imaginable for any aquarium. They trap waste and create ammonia which as any Aquarius knows creates all bad things that could ever go wrong on an aquarium. REALLY??! Have the designers ever used one of their products? They puke up HUGE amounts of waste deposits EVERY TIME. They are restarted. Cleaned. It is impossible to clean the ribbed hosing.
Just bought a fluval 406 and apparently it is missing the media basket cover. Is that going to be an issue or does is there a part I can buy at a later time and still run it?