Fluval Underwater Filter

There are many things to like about this filter. It is completely silent, quality built and versatile.

For a Turtle tank setup with part water setup, it can be laid on its side and create a fountain effect. It does a great job in comparison with the Whisper filters that can be stood up.

I use the U3 for my 29 gallon community fish tank. I take turns every month changing each carbon filter and occasionally change the bio-max (in the middle) and foam (on each side).

This filter as stated above is completely silent.. I mean completely. That alone is a attractive feature to many. Controller the water current will be attractive for plant tanks.

I do really like the Aqua Clear filters but have run into one issue twice. When the power goes out and if the filter is not unplugged before it goes back on, it will burn out the motor. It cannot prime itself. That is why it happens. This filter is fully submerged in water so that is a non issue. I have had this filter for three years and it is still going strong.

One possible downside is the fact in some peoples tank, it may appear as a sore spot. By that I mean it is a big black filter hanging inside of the tank, very visible in comparison to hang on the back filters.

One small note. the suction cups on this are VERY STRONG. I seriously thought I was going to break the filter attempting to move it, that scared me. It comes with four suction cups. I only use two and it works perfect.

I sell filters all the time for a store and these filters are a steal for Amazons current $45. Most people are paying $90 for this filter, as I did when it was new.

I am not trying to say it should be compared to canister filters because obviously they will do a better job. In comparison to hang on the back filters, I would easily recommend this filter.

Do not buy the U1 filter as the smallest one does not have a carbon insert, all it is, is a piece of foam. The U2, U3 and U4 are great though.

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UPDATED 7/26/12-see bottom part of entry-upgrade from 3 to 5 stars

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Original review June 2012:

I'm writing a long review because I found it helpful to hear others' experience specifically with turtles. They are a little different than fish when it comes to what works.

I have a painted turtle, about 5-6 inches long right now. We have an algae eater too who helps keep the tank clean (we call it a sucker fish, not sure what its real name is). We also periodically add small minnows and goldfish to entertain the turtle and for food if we forget to feed her or go on vacation. Since she's primarily a water turtle, her tank consists of mostly water with a few haul out spots.

We just upgraded from a 20G tank to this one. Previously we've always used the Whisper Quiet filters with great success. People would rave about how clean the turtle tank was, and we could pretty much ignore it (don't worry about changing water, etc.) In the 20G tank we had the 20-40G Whisper Quiet in about 16G of water, no plants, a few submerged items, and a floating plastic "log" for basking. For the 50G, we added a few more submerged and surface items, but all are plastic or rocks, nothing living.

Upgrading to the 50G tank (with about 40-42G water) posed a problem for me. All of the larger hang on back filters required the water level to be higher than I wanted, since the turtle needs some land, and I didn't want it climbing out. I tried rigging a few up-the larger Tetra one worked very well, but I had to rig it inside of the tank, and it just took up too much room.

I decided to try the underwater Fluval for two reasons-never need to worry about water level, and because I'm not willing to invest in a canister filter.

PROS:

--silence. it's golden

--ease of changing filter media (it's really simple, you can lift it up so you don't contaminate everything or spit junk back out)

--will never dry out or burn out if you lose power and it restarts (since submerged)

--ability to place where I like in the tank for optimal filtering and flow to stir things up

--ability to change parts of filter at a time to preserve beneficial bacteria

--foam pad separate from other pieces so you can rinse that and not everything

--no splashing, so no hard water stains on side of tank

CONS:

--I want to love this filter and I hope it works long term. We used it in a tank that had been recently filled and set up, with the Tetra running for about a week. Initially this worked really well, but about a week into it, the water turned nasty green. First off, TURTLES ARE DIRTY. By nature I don't think this filter accomodates that. I'm holding off judgement since it sometimes takes a while to get things right when you set up a new tank, as it happened before with other filters too at times. However, in this case, I think it's because of a lack of active carbon in the filter. There is just a tiny bit there, and in my experience (6 years with this turtle), the active carbon is ESSENTIAL to keeping them from getting stinky and gross. I decided to remove the bio pellets from the middle part (step 3) since I never had them before in my tanks anyway, and instead fill that space with one of the tetra filters filled with activated carbon. It's been about 10 hours. The nastiness is gone and the tank looks much better. There still seem to be a lot of particles in the water, but I am continuing to work on that-not sure if I can blame it on the filter at this time. I will keep adjusting, because I think this filter is worth figuring out how to make it work for turtles.

I gave it three stars because it advertises that it can be used for my purpose, but I don't think it comes through with the media it uses. I also think their media replacements are expensive relative to other filters (which is especially frustrating when they aren't even working for me). However, if the makeshift adjustment of using other carbon filters inside the third chamber is effective, I would upgrade to 4 stars. If I get to perfectly crystal clear water without the need to pay attention to the tank every week (yes, it's possible with some cheap filters), I'd go to 5 stars. I ask a lot from my filters!

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UPDATE 7/26/12

This definitely deserved the upgrade to five stars. I had to leave for three weeks after adding the Tetra carbon filter to the center in place of the bio pellets, so I filled it with a bunch of minnows for her to eat over time, then came home to a tank that was still crystal clear after 24 days. (Trust me, I was almost afraid to look at the tank when I returned for fear of how gross it might be.) A few minnows were still swimming around happily too. I went ahead and swapped out the carbon filter, but it looks like I can simply wash out the outer sponge and pathetic carbon insert supplied with it periodically and replace the Tetra carbon insert in the center chamber monthly. I still don't like that I had to adjust it, but I don't think there's a great product out there for turtles, and this is working VERY well. Plus, I am now purchasing the cheaper Tetra filters, so my ongoing costs will be less.

If you go this route, it does seem like a very tight fit to fold over the Tetra filter and slip it in the middle chamber, so don't be shy. Just wiggle it as you push it in and be gentle.

All that remains to be seen is longevity, but for now I am one happy consumer!

Buy Fluval Underwater Filter Now

I got this for my 10 gallon aquarium and I was amazed by how well it filtered my water, I was never a big fan of in-the-tank filter but man this one gets the job done! I wish I could give this a 4.5 stars but I can't, only reason I didn't give it a 5 star is because its pretty bulky and kind of unattractive to look at and due to the size its kinda hard to conceal behind plants. Its COMPLETELY silent, if you don't need the filter to provide aeration its pretty much impossible to hear it unless you press your ear up against the glass next to the filter. The filter does provide an option where it can provide aeration, unfortunately any type of aeration (from any filter or a air stone) will cause sound due to bubbling and surface agitation.

Read Best Reviews of Fluval Underwater Filter Here

I really like using canisters when I'm able, but one of my tank configurations wasn't lending itself to a canister and I don't like the constant noise of the water fall from Hang On The Back filters. I thought I would give this a try.

Super easy to install. Very simple to maintain. Good volume of water flow and I love that you can run top, bottom, or diffused center output. The diffused center output also has adjustments to direct the flow 45 degerees left, straight, or 45 degrees right. I can't imagine that one of the settings wouldn't be prefect for just about any tank.

I LOVE how easy it is to remove the filtration media inserts. It does not require you to remove the filter to wash out the media. However, removing the whole filter from the holder isn't difficult at all (if you ever needed to). I do wish they had a non-carbon filter pad for the outside slots though. All you really need is polymesh unless you are removing medication from the water or trying to clear the tank from tannins if you use real wood in your aquascape. The use of carbon increases the filter cost and it isn't actual carbon, just crushed carbon media impregnated on a filter sheet. I would be more than happy with just a water polishing media insert.

Only a couple down sides, which is why it didn't get a 5th star. The way the filter fits in the mount leaves a space behind the filter above the filter mount that is about and inch wide and 4 or 5 inches high. It is just enough for a slender or small fish to fit through. It hasn't been a problem (yet), but I can definately see a fish getting stuck as they get larger. Or, freaking out and injuring itself thinking it is getting stuck. I might insert a sponge or something back there to prevent fish from swimming through it.

I don't know it it is just mine, but the upper output nozzle has an aeration feature with rubber plug that is supposed to be able to adjust the aeration amount as you turn it. But, there is no way to stop the aeration. I think my plug may just not be sealing correctly, but I removed the plug and used regular air line with an external ball valve to solve the issue. this also allows for external air to be pumped into the tank causing air turnover. Otherwise, if you just close the lid and aerate from under the lid there is no air volume exchange.

Fortunately, the aeration fitting is the perfect size to fit air tubing. I just inserted the air tubing and it was a tight enough fit that I didn't even need to use anything to seal it.

All in all a pretty good unit. I really do like canisters a LOT better though. I wouldn't hesitate from buying another if I couldn't use a canister though.

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UPDATE

I lowered my rating from 4 stars to 2. The space behind the filter did turn out to be an issue trapping a Gold Barb. But, the larger concern was the lack of adequate filtration. I'm comparing this to the Fluval 106 canister filter I replaced it with.

Simply, the 106 rated at 90+ gallons per hour circulation is so much better than what's available with the U3 (rated at 155 gallons per hour) that it isn't even comparable. I wasn't getting adequate circulation and my 20 gallon long tank wasn't staying clean or clear.

I think part of the issue may be that the output and input are at the same location, which only allows enough circulation for a portion of the tank while the 106 I seperated the output on one end and the intake on the other. Even though it is rated at less, the 106 is (by far) supplying better filtration.

I'll keep this and use it as an emergency back up in case any of my other filters fail. But, I will no longer use it as a primary stand alone filter.

Another concern is that having to use specific filter pads, which increases the cost of operation. With the 106, I can share media with my other canisters and don't need to buy specific panels during maintenance.

The ability to purchase bulk media will offset the cost over time and moving to a canister filter is easily the better choice.

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After a week of usage, I can safely say I am amazed by options offered by this filter. I have a 30 Gallon Tank and Turtles and the u4 is doing a great job of keeping the tank clean.

This filter is placed inside the tank either straight up or laid down. It has three options for filtering. A, is the strongest current, B, utilizes the filters spray bar for an even flow, and C takes care of the bottom of the tank.

I was pretty amazed at how much power this filter has, it creates a mini river flow in the tank. This helps debris circulate towards the filter and provides my turtles some fun as they exercise their way through the current.

The filter it self has a 3 stage filtration. It uses 2 foam pads and bio nodes to help keep the tank clean, there are replacements available online if you so need it. On top of that accessing these foam pads and bio nodes is made easy with the filters flip top.

Another option this filter has is outputs for a bubble wand or any other tube like apparatus.

And one last cool thing that this filter comes with its own detachable "holding cradle with suction cups." You tilt it forward slightly and you can remove the filter from the tank for easy cleaning.

Overall I give this filter 5 stars for its sleek design, many options, and great filtering. I do recommend this filter for both turtles and fish owners.

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