






💧 Elevate your aquarium game with whisper-quiet, crystal-clear flow!
The FLUVAL U4 Internal Filter supports up to 240 litres with a powerful 1000 L/hr flow rate, featuring a 3-stage filtration system combining biological media and activated carbon. Its adjustable flow control offers versatile spray modes, while the ultra-quiet, sleek metal design fits discreetly inside your tank. Easy top-access maintenance keeps your aquatic environment healthy and vibrant.






| ASIN | B001XRXY1G |
| Best Sellers Rank | 5,528 in Pet Supplies ( See Top 100 in Pet Supplies ) 23 in Aquarium Filters |
| Brand | Fluval |
| Capacity | 240 litres |
| Customer Reviews | 4.2 out of 5 stars 7,852 Reviews |
| Global Trade Identification Number | 00015561104807 |
| Included Components | Filter |
| Included components | Filter |
| Installation Type | Freestanding |
| Installation type | Freestanding |
| Item Type Name | HAGEN FLUVAL U4 UNDERWATER FILTER |
| Item Weight | 1.12 Kilograms |
| Item height | 14 inches |
| Manufacturer | HAGEN |
| Material | Metal |
| Material Type | Metal |
| Maximum Flow Rate | 1000 Litres Per Hour |
| Model Name | Fluval A Filtro Interno U |
| Model Number | A480A1 |
| Power Source | Manual Operation |
| Product Warranty | FALSE |
| Purification Method | Biological filtration, activated carbon |
| Purification method | Biological filtration, activated carbon |
| Supported Water TDS Level Maximum (PPM) | 300 |
| UPC | 015561104807 764999862437 155611048009 015561104784 015561104876 081175371515 |
| Unit Count | 1 count |
| Upper Temperature Rating | 80 Degrees Fahrenheit |
T**E
Must have !
Best in tank filter I’ve had. Bought as original tank filter went down in my 130l , the pros of this filter are - -super quite , hardly any noise -smart looking / blends in / fits nicely -3 different spray modes (top , bottom or middle for gentle flow) So easy to use / setup and for maintenance The water is really really clear with the active carbon in the filter , it comes with ceramic media too which is a bonus Overall really good filter , highly recommend this in tank instead of external canister
P**G
Good filters, quiet in operation
Brought to replace a failing one. I find these last a few years and then start failing. I like this filter, it is quiet and does the job well. Needs cleaning about every 2 weeks in my 100L tank.
S**Y
Amazing filter top marks all round
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
A**N
Good filter, but frustrating to service
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.
A**A
Good filter
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
L**G
Poor performance
We are today replacing this filter as since this was put into place mid Oct , the water has been cloudy and had to be changed weekly , we have a 200 litre tank so this should have operated fine but the results are really really poor . Would not recommend this product
D**N
Quiet, powerful, and a great upgrade for small to medium tanks
I recently upgraded to the Fluval U2 Underwater Filter after using the standard filter that came with my Pets at Home LoveFish tank, and the difference is huge. The old filter felt like a gentle trickle in comparison. This one actually moves the water properly and keeps it clean and clear. The Fluval has three flow settings depending on what you need, top, bottom, or full middle. I personally use the top outlet with the nozzle angled towards the surface. This keeps the surface water moving and means I no longer need to run a separate air pump. There’s less tubing in the tank, far less noise, and lower power use overall. I’ve been running it for about a month now with no issues at all. It’s easy to maintain, runs quietly, and feels well made. I’m using it in a 64L tank with shrimp, tetras, and snails, and the flow is just right, strong enough for good circulation but gentle enough for smaller fish and shrimp. I got it for £40.50 it’s great value for what you get, especially compared to the basic filters that come with starter tanks. If you’re still using one of those, this is a solid upgrade that makes a big difference to water clarity and general tank health.
A**R
NOT UK PLUG!!!
Absolutely nowhere in this advert does it say that it doesn’t have a uk plug?? It has a European plug so if you’re in the uk and buy this have an adapter handy. The filter itself is great though been using a u4 for years
Trustpilot
2 weeks ago
2 weeks ago