Fluval U1 Underwater Filter, Freshwater and Saltwater Aquarium Filter, A465, Black

This filter is on a 10g freshwater tank with 5 fish. Our old filter (one that came with the tank) was getting constantly bogged down after a few years of use. Even after freshly replacing the filter inserts, it was not moving enough water to keep the tank clean. With our tank positioned near a window where it gets an abundance of indirect sunlight, it was growing algae faster than the bogged down filter could clean it. We purchased this filter as a replacement based on its price and our previous positive experience with the Fluval brand. The filter was very easy to install, and fit easily into the space where the previous filter had been. Within a few minutes we had it running, and within maybe 2 hours, the tank was clearer than it had been in months. This filter moves a lot of water. It is very quiet - the only noticeable sound is the water itself, it is easy to maintain, and it does a phenomenal job of cleaning the tank.

Was so happy after I got it .. worked awesome … could see the water flowing out in a nice stream … quiet … I did a 50% water change .. unplugged it .. checked to make sure the filter was clean … now I can’t see the water flowing from the nozzle .. I can feel it if I put my finger in front of it that’s all … I’m so disappointed.. now I have to put a bubble stone to make sure the water oxygenating! However I after a lot of googling I figured it out!!!! Unplug it but leave submerged .. turn it upside down under water a give it few good shakes … it dislodges anything stuck .. but it also releases trapped air … while it’s under water turn it right side up … position it how u want to … plug it back in … and with in seconds the water is moving again beautifully!!!

Was very excited to have this filter. Before I open the box I heard a “gling gling” sound. Didn’t know what it was until I opened the filter. The impeller was broken; the pales was in pieces. Impossible to make it functional. Had to order a brand new impeller $$. Very disappointed. UPDATE. After I received a new impeller and installed it, I can tell this filter is very good, efficient and it’s a breeze to clean. I recommend and would buy again.

This is just a poor filter. I have a least one each of Fluval U1, U2, U3, and U4 in my various aquariums. The other filters in this series are fantastic. If you’re considering the U1, I would go with the U2 and have a little more filter than you think you need.

Update: after using this filter for two months I have reduced my rating from 5 to 3. It's incredible how fast the filter media gets clogged thus reducing the outflow of the water. I literally have to change the filter and filter media and completely clean the unit every five days or it almost completely stops pushing out water. Not a happy camper. It does not suction well and there's tons of debris floating in my aquarium although I gravel vac every week. I would not recommend this and I'm disappointed and Fluval. I purchased what's called a bookshelf tank. It is 35 inches long and about 9 inches deep. I set it up with two sponge filters on either end and it just was not cutting it. I had a dead zone in the middle. I replaced the sponge filters with this pump and let me tell you, it is awesome. Whisper quiet and just enough power to shoot the water gently across to the other side of the tank. I couldn't be happier. It's adjustable also which is an added bonus. Highly recommend.

I added the U1 to my 20 gallon tank that already had a 20 gallon filter. I wanted some flow, and extra filtration since I have a few more fish than I should. The sponge covers all inlets, so my Kuhli Loaches and shrimp aren't at risk of being sucked in, which is extremely nice. Any other filter or pump I've used required me to superglue sponges or screens to the inlets. I also love that the sponge is easily removeable via the lid, so I can pull it out and clean it without moving the filter. It also has a removeable piece in the center that I removed and replaced with a media bag full of Zeolite and Carbon blend with some compressed peat for acidity. Mounting the filter was the only downside I had with it, but because of the easily removeable sponge I'm not knocking off a star for it. The U2 and higher models have a bracket, the U1 just has 3 easily removeable suction cups (not a good thing) so once you stick it on the glass, if you even try to move it the tiniest bit to position it just right the suction cups disconnect from the unit and stay stuck on the glass, forcing you to pry them off, pull out the filter, reattach the suction cups, then reposition it again. That said, it stays put, its fairly small, and looks nice. For a filter that attaches to nothing but the wall, it's very quiet. Much more so than the two cheaper units I used. Obviously a HOB will be quieter since it isn't attached to the entire tank turning your tank into a giant vibrating subwoofer, but for something that DOES transmit all of its vibrations straight into the tank its very quiet. My Marina HOB is quieter and the U1 does make a very faint grinding noise, but I can only hear it right next to the tank and 5 feet away it is inaudible. Filtration is great as well. I use it as a second filter, since my HOB is stuffed full of loads of different media so the flow rate is lower, so this serves primarily as a bio-filter to reduce ammonia. For that purpose it does fantastic, and the small media bag in the middle for some extra filtration is nice too. The flow is the best part here though, it keeps my substrate crystal clean and any gunk that gets kicked up by the loaches or cories immediately gets swept into the current and sucked up by the filters. If you're using this as your only filter, definitely add some zeolite and carbon to the middle of it. All said, it's a fantastic filter and I honestly wish I just had one U2 for my 20gal rather than two separate filters.

I was excited to buy a new filter. But for a “15 gallon or less” this filter is HUGE. It definitely takes up a lot of space just for a 10 gallon tank. However, it is a power house. The plastic used does seem a bit cheap, but it comes with a pretty big sponge that had a very strong chemical smell for some reason. It also did not come with filter media but perhaps I didn’t read the description. However, this filter really cleaned up my axotlol tank when a regular sponge filter was just not doing the trick. So far so good.

This filter is everything my friend said it would be! It works for exactly what I needed it for. I have it in my 5 gallon partially planted(some are live some are fake) betta tank and my fish couldn't be happier! as soon as I placed it in the tank, Freckles (my betta), was all about it. He was resting on the top of it for most of yesterday. And it doesn't beat him around the tank either, which was what I was worried about with most filters. And the filter is also very flexible about what kind of media you can put inside it. I just stuck with the foam pad it came with since I have plants. I don't need carbon filters zapping the nutrients out! But yeah the bottom line is that it: Makes a gentle current for both my plants and fish, it's quiet, flexible with filter media, and it's compact enough to fit into a 5 gallon fish tank. If you have a 5 or larger this filter is amazing!

I wanted to buy a quiet a filter for my son's bedroom aquarium and boy is this quiet! Wow. Standing next to the tank and with the filter submersed I can't hear a thing. I honestly cant fault the filter in anyway. We have a 35l tank and the water is crystal clear for about a month now. Cleaning was easy and the fish are happy. Great product.

The unit don't work $5 temu product did a better Don't trust German product are good Buy this product, you waste your money I have one left not use, get it from me for half price

This product is very good for aquarium. Specially it did not create sound and also filter the water very well.

J'ai commandé le Fluval U1, car mon ancien filtre Fluval (que j'ai gardé 15 ans) m'a lâché. Le filtre est très silencieux, notice en Français avec images d'illustration. Entretien facile, fournis avec une mousse filtrante. Prix un peu élevé, mais produit de qualité. Je vous le recommande.

Ich suchte einen ganz leisen Filter für mein Kaltwasseraquarium und habe viele Modelle (3-5 Watt) getestet. Auch Modelle von Eheim und Tetra. Der Fluval U1 Innenfilter ist überzeugend leise. Der leiseste Filter bisher. Überzeugendes Konzept, da Vibrationen des Motors durch eine besondere Befestigung nur stark gedämpft an die Aquarienscheibe weitergeleitet werden. Zur weiten Geräuschreduzierung habe ich den unteren Saugnapf vom Filter nicht befestigt, keine Düsen am Filteraustritt angebraucht und den ganzen Filter knapp unter Wasser angebracht. Es wird keine Luft angesaugt und eingeblasen. Ich bin mit dem Filter sehr zufrieden. Bei dichter Bepflanzung und geringer Fischbesetzung im 160 Liter Becken, geht es mir insbesondere um eine leichte Wasserbewegung ohne Geräusche. Die Glasdicke meines Aquariums beträgt 8 mm was vielleicht auch Vibrationen (Geräusche) reduziert. Kleiner und nur etwas lauter empfinde ich den Eheim Innenfilter (Eheim Pickup 60) den ich bisher benutzte.