Fluval FX4 High Performance Aquarium Filter, up to 250 Gal. | Canister Filter for Aquariums

I have kept fish for about 50 years. I have experimented with many aspects of the hobby, studied everything, and done trail and error. Now I just run one 150 gallon tank, but at times have had many. I also have out door ponds. What I know is that most crap you read from so called experts on the web are "crap". After 50 years the basics are the same. The equipment has improved. Most people have no clue as to what a filter can do or should do. Go to my forum at yardcraphome dot com and open the critters section. I hooked this fx4 in today. I have been running the older fx5 (new model is fx6) for years and consider it a good buy. The fx5 had some challenges as to leaks and easy to break clamps, but suspect/hope they improved with the fx6/fx4 update. The fx5 is very good, best filter I have owned. Flow rate is important, but also is volume. These fx6/fx4 are huge. If you just want flow, buy a circulation pump. What you want is the water to pass over lots of helpful things before returning to the tank. I use multiple filters for different things as that helps as to maintenance. . One (fx5) is mainly for biological which is by far the most important. Due to the great 900 gal output, have it hooked to a a Tetra Pond bio filter that they claim handles 4000gal (doubt that). That reduces flow rate, but the combination is over kill for biological in my tank. The two together are like a large, but closed sump filter which can hold lots of bio material. The now dead Fluval 300 (or something?) was for chemical and needed replacement. I looked at filters to replace it and almost went with the new Ehiem 600 (great filters), but in the end got the small brother of the large Fluval that is still working great after years. I decided on the fx4 as opposed to the fx6 due to the fact the volume was enough when just for chemical, and I don't want my tank to become a rushing river. One thing with these is adjusting flow rate is very easy so maybe should have gone with the fx6. I hooked it up today and the only problem was a leak at the input connection. I wrapped some Teflon tape and easy fix. I filled it with Chemi-pure (because I have used it for decades) and and Purigen (which is just an excellent product). The flow rate is not that much more and my fish friends are large fish. I don't think flow reduction will be needed. My opinion is that for many, the fx4/fx6 is a best buy. The down side is they are large. Large is also the good part, but maintenance must be done from time to time so keep that in mind. These are heavy. I have a small room with a sink where filters live and tubes pass through the wall, so easy for me. My 3rd filter is the Fluval G6 which is a joke. This would be good for a nerd type with a small tank with low fish levels. I only keep it hooked in for the mechanical cartridge (no where near as good as the older Magnums, but very easy to service). Mechanical filtration occurs with all filters and while nice, should not be the focus of your filter choices.

Great filter, bought for my 75 gallon tank. It is keeping the water crystal clear. Set up was real easy and I’m quite shocked how quiet the filter is when running. I have not had to do a water change yet but it seems pretty easy with the built in drain at the bottom .

I have a 75gallon planted community tank. This has great flow that can be adjusted, my tank was decently clear but this baby did wayyyyy better than my penguin 350 HoB. I love the customizable trays. Replacing media is a breeze and everything seems sturdy and reliable, it's super quiet

So, it's only day one of having my tank filled and filter running, but that's all I needed to have enough information to write an initial review. Why? Three reasons. I'll start with the easiest...as with my experience with the Fluval 306 in the past, the FX4 is extremely quiet, which is an absolute must!!! Second, the filter is extremely easy to set up. Finally, because I don't have any standard faucets where I can use a hose adapter, I tried a couple other ways to fill my tank...both of which failed. I finally decided I would just carry buckets of water over to the filter and try out the pump function of the FX4 and HOLY MOLY, what a life saver!!! Yes, with a 120 gallon tank, it took 20+ trips from my kitchen sink to the aquarium (I'm going to figure out a simpler plan for water changes that's for sure :) ), but the pump function work flawlessly and vwalla, tank filled! Fluval has never let me down. This is the third filter of theirs that I have used... I definitely recommend them to anyone trying to decide which one to use.

when i was researching this for my 75gal tank someone called it a beast and they weren't wrong. this thing took my cichlid tank from days without a filter to crystal clear in 24hrs. its super quite.

Great filtration and very quiet. It was easier to start than other canisters I've used.

I bought this product July of 2020 it was working great until May/June of 2021. I bought the 3 year warranty with this product and contacted Fluval when it started to mess up. I cleaned the filter out and all the hosing and it still would not work. It would not even make a noise like it was trying to start anymore. Fluval emailed me back and wanted me to clean out where the motor is. I did this and it still was not working so I emailed them again and then they stated they wanted pictures of the clean filter so i had to do this as well and send it. Then they decided they wanted pictures of the entire set up. Basically every time i talked to them they came up with more excuses as to why it wasn't working properly. I followed the instructions verbatim when setting this filter up and like i said it worked great for over 9 months. Each email they sent had a different excuse as to why it was not working. I even took the motor area apart and took a video of it plugged in making a noise like it wanted to work but not rotating properly. As this point i am getting very agitated. I paid around $300 for this filter and the 3 year warranty and they are refusing to uphold their end of the deal with the warranty. This has been over a month now that i have been emailing them trying to do everything they say and my turtle is struggling without filter and they have done everything they can to make it difficult and to make up excuses as to why they aren't honoring their warranty. I have never written a bad review but this is very frustrating and costing me a lot of money that i do not have. The whole reason i purchased the fluval was because of the warranty and the fact they aren't honoring that is infuriating to me. So if you are thinking about purchasing their products keep in mind they won't honor their warranty .

Had this for about a year and a half. No issues until the last month. Clean it just like I have been doing all along. Went to feed fish one morning and it was off. Fish were all staying down low and were acting strangely (aggressive). Unplugged it started to work, shut off. Waited 10 minutes, never went back on. I cleaned it like always (with caution), it now has a leak in output valve. I have to keep filter on low because it leaks if I barely turn it up. so the output isn’t what it needs to be for the size of tank. Not sure where or what to do yet. Since it should have a 2 year warranty. I don’t need all my fish to die. Right?

Llego a timpo y en perfecto estado, ya lo instalé y es un gran filtro no tan solo por su potencia sino también por ser muy silencioso

Es un filtro brutal, con una salida de agua tremenda, bastante espacio para material mecanico y biologico, tambien puedes añadir quimico sin problema, por poner alguna pega, la bandeja del material biologico baja demasiado hasta encajar en la otra y no permite llenarla entera, aun asi cabe bastante, es recomendable aunque sea pesado no poner el material tirado como caiga, se pone en vertical uno a uno y cabe mas, con el que trae esta bien, pero yo he añadido mas. Los cierres no me gustan porque son pesados para abrirlos y se ve un plastico normalillo que no malo. No se puede regular y los tubos son un poco rigidos. Recomendado

Şu ana kadar aldığım en iyi dış filtre parasını hak ediyor

Super Filter, reinigt sehr gut das Wasser. Einfach zum reinigen und wasserwechsel natürlich super easy

Zeer snel geleverd tegen de laagste prijs. Het is een beest van een filter met een zeer grote netto capaciteit. Ben er zeer tevreden mee. Het is een geluidsarme filter die zeer onderhoudsvriendelijk is. Door de degelijke bouw en kwalitatieve accessoires is het een genot om hem aan te sluiten en in gebruik te hebben.