Fluval U4 Internal Filter, 240 Litre

Really good filter. I've been having it for years now and honestly im really happy with it. Im using it in a 90L tank, works great, not too strong water flow, which is good for my lazy fish. Its easy to assemble and clean, quiet (especially if fully submerged) and not too heavy. There's no smell from it if cleaned properly

Typical Fluval quality & a very well thought out filter. Extremely pleased 😀

We bought this as the filter we had was not doing a great job water was never crystal clear. Bought the u2 and over night the water was clear.The pictures added to this review are from this weekends water change/aqua scaping. The water got super cloudy due moving the sand about. With in a few hour a noticeable difference. This morning the tank was crystal clear. Out water is dark due to new wood tanens being in the water. But the water its self is beautifully clear. Quiet filter and easy to use. It is quite a big filter. We have ours hidden behind some wood. The three settings for bottom middle or top flow is great to have. Easily removed for filter changes. I cant recommend high enough. You can feel the quality.If you order this get a eu to uk convertor plug as mine came as an eu plug and not a uk one. Wasnt an expensive add. Even that doesn’t take away for how great the filter is

This is an update. I bought this filter in 2013, and the thoughts listed below are those I had after ten months of use, but before I list them, I should say it has given me five years of good service, which is pretty good. It is still working, but I have decided to retire it as the coating on the wiring was getting very 'iffy' after having been threaded in and out of the clips so many times, and the last thing one wants, of course, is to be electrocuted. So, in addition to my other thoughts about it, I would suggest that you do test the coating on the wiring, just to make sure it is not wearing thin. I originally gave it three stars, but for length of service, I have upgraded it to four.I have a 160L tank with five fancy goldfish (body length 7-8 cms) that have also been in the tank for most of that time. I also have an Eheim 160 pickup filter in it, each acting as backup for the other, but both are still going, although lately I have been using the Eheim to add API Aqua Detox filter to try to reduce the nitrate levels -- my only water-related problem. As far as the Fluval U4 is concerned, the only problems I have with it is when I need to rinse it out. Perhaps these don't sound too bad, but when you are dripping water everywhere, speed is important, and this is time-consuming, and frequently frustrating if you don't happen to have the right tools on hand. First of all, the top is impossible to remove without a lever of some sort. Once that is removed, if you are simply rinsing out the sponges -- I don't bother with the carbon filters unless I think the water could do with a bit of polishing now and again -- you can leave the filter where it is, and lift them out and rinse them in tank water you've removed (obviously), before returning them to their slots, the same with the biological media. However, if you find the filter running slowly because the impeller needs cleaning, that's a whole different ball game, because you'll need to remove the whole unit from the tank. In order to remove the impeller section from the rest of the filter, you will need to unhook the electrical cord from the upper section, a real hassle when you come to the top clip, and even more of a hassle when you go to replace it after cleaning. Cleaning the impeller and its housing, something that needs to be done at least once a month (goldfish are messy), is relatively easy providing you have pipe cleaners or a bunch of Q tips handy, but then you have the task of replacing the electrical cord in all its little clips, and the top one, as I said, is a real hassle as it will go in only if the cable is sideways on, then must be twisted to flat position to hold it there, all made more frustrating because everything is not only wet, but slimy. Getting this right is essential, though, because if the cable is not seated properly in its clip, then the whole unit will not clip into the frame holding it flat against the tank, and trying to force it, will no doubt break the clip, as happened to one of the other reviewers. One other problem I find it with the knob that determines flow and direction. It can be quite easily moved around, and if it slips out of position, it can stop the flow altogether. Other than sticking my hand in the water to check that it's still working, I have to rely on the movement of nearby plants to judge the level of flow. As a filter I have no problems with it, nor with the Eheim if it comes to that, but for ease of cleaning I'd go for the Eheim.

Lasted 5 days before started rattling. As well don't believe it actually had described flow rate. Good design but quality don't match asked price as it come with broken lid hinge and the mainreason for returning was it starter rattling. It did keep the water clean however the water was clean before I put it in. For me returning is automatic 1*. Unfortunately I'm on square 1 looking for filter.

Fluval Filter for U2 has proved a valued asset to my tank and is the second one purchased.Does an excellent job filtering the water as well as air-rating the water.Quite easy to set-up and regularly change the filter pads, etc.The cost was a little high but it does the job!Delivery good.Would highly recommend this filter.