PetSmart Ratings and Reviews

Customer reviews for Fluval(r) Underwater Filter

This product is no longer available. Continue shopping at PetSmart.

Fluval(r) Underwater Filter

Enjoy improved water clarity in your aquatic environment with this underwater filter. Featuring a 3-stage filtration system with BIOMAX, the filter collects debris and removes impurities to ensure water quality. The 3-way flow rate adjusts for output flexibility, while the flip-top design makes cleaning simple.
Overall rating:
4.619 / 5
4.6
 / 
5
(21 reviews) 20
19 of 21(90%)customers recommend this product.
Reviews for Fluval(r) Underwater Filter
Review 1 for Fluval(r) Underwater Filter
Overall rating 
5 / 5
5 / 5 21 reviews

Most amazing filter ever~~

March 4, 2014
by MzTee
fromRichmond Hill, Ontario
What is your gender?F
How many pets do you have?5 or more
How often do you shop at PetSmart?Weekly
I recently got the U1 for my 5.5g since I had gone through 3 different TopFin filters and they were all horrible and at first I thought it might be too strong for my shrimps but they are doing pretty good. To my surprise it is actually extremely quiet. There is a very low humming sound but its still more quiet than my laptop so this is already amazing. The only thing about it is that I have shrimp and I was afraid they would get sucked into the intake and i know people are saying to just put panty hose on it but then it would clog up really fast and so I just ended up buying some carbon pads and cut them in half and put it on each side. It is now shrimp safe, quiet, and efficient. This thing is worth every penny.
I honestly think they should fix the U1 to be more like the rest of the other models (U2,3,4). That way it would be PERFECT!!
0points
0of 0voted this as helpful.
Review 2 for Fluval(r) Underwater Filter
Overall rating 
3 / 5
3 / 5 21 reviews

Probably not for Gold fish

February 11, 2014
by DonnaSue
fromMontana
What is your gender?F
How often do you shop at PetSmart?A few times a year
Performance 
2 / 5
2 / 5 21 reviews
Quality 
2 / 5
2 / 5 21 reviews
Ease of Use 
3 / 5
3 / 5 21 reviews
Unit wouldn't work at first, the impeller would stick. It still sticks every time I pull it to change the filters (need to either shake it or open it up). I was hoping for better water quality - but since I have gold fish (and probably a little overcrowded too) it is probably doing all it can do. Unit is hard to re-attach after removing it from the bracket and changing the filters -- the suction cups on the bracket keep moving down the aquarium; requiring you to put both hands in the aquarium to reattach the unit to the bracket. Filters are good though and capture a lot.
Pros: easy to clean
+1point
1of 1voted this as helpful.
Review 3 for Fluval(r) Underwater Filter
Overall rating 
5 / 5
5 / 5 21 reviews

Accurate recommendation of usage gallon

January 25, 2014
by Jenn51
fromSan Gabriel,CA
What is your gender?F
How many pets do you have?5 or more
How often do you shop at PetSmart?Monthly
Performance 
5 / 5
5 / 5 21 reviews
Quality 
5 / 5
5 / 5 21 reviews
Ease of Use 
5 / 5
5 / 5 21 reviews
It's so powerful, get all the waste and debris in short time..better follow the recommendation..first use U2 but it too powerful to my fish..put it back and get U1 instead..my fish so happy
Pros: easy to clean, works great, easy to install
0points
0of 0voted this as helpful.
Review 4 for Fluval(r) Underwater Filter
Overall rating 
5 / 5
5 / 5 21 reviews

Very Powerful and Effective

December 29, 2013
by JimInAtl
fromAtlanta, GA
What is your gender?M
How many pets do you have?5 or more
How often do you shop at PetSmart?Weekly
Performance 
5 / 5
5 / 5 21 reviews
Quality 
5 / 5
5 / 5 21 reviews
Ease of Use 
5 / 5
5 / 5 21 reviews
I'm very impressed with these pumps! I ordered these for tanks that I set up ton my kitchen bar top, because I didn't want the visual distraction of hang-on filters, or to lose any counter top space to canister filters.
Mine are the U4's, which are in 20 gal tanks - I ordered the largest ones, because I had read some forums suggesting that internal filters were not as effective - not true in this case!
Having them inside the tank makes them completely silent.
The flow rate and direction is very adjustable, and the internal filters slide right out of the top, making them super easy to clean.
I will definitely be buying these for future tanks, but I will adhere to Fluval's sizing recommendations, as they are accurate!
Pros: easy to clean, works great, easy to install
+1point
1of 1voted this as helpful.
Review 5 for Fluval(r) Underwater Filter
Overall rating 
5 / 5
5 / 5 21 reviews

Better than previous filters I've tried

December 1, 2013
by BobLobLaw1991
fromVisalia, CA
What is your gender?F
How many pets do you have?3
How often do you shop at PetSmart?Weekly
Performance 
5 / 5
5 / 5 21 reviews
Quality 
5 / 5
5 / 5 21 reviews
Ease of Use 
5 / 5
5 / 5 21 reviews
I purchased a different filter previously for use in a 55 gallon turtle tank. That filter was incredibly disappointing. It was difficult to put together and didn't work at all. I was reluctant to buy another filter since I had spent so much on the last one and it didn't work. This filter works so well though; it was the complete opposite of he first filter. I do not regret this purchase. It cleared up the water quickly and even removed the difficult debris on the bottom that I couldn't manually remove. The directions were simple and it was easy to put together.
Pros: easy to clean, works great, easy to install
+3points
3of 3voted this as helpful.
Review 6 for Fluval(r) Underwater Filter
Overall rating 
5 / 5
5 / 5 21 reviews

great for most fish

November 16, 2013
by bettafishowner1234
fromohio
Performance 
5 / 5
5 / 5 21 reviews
Quality 
5 / 5
5 / 5 21 reviews
Ease of Use 
5 / 5
5 / 5 21 reviews
This system is a great filter. i bought it for my 10 gallon fish tank for my betta fish. unfortunately even on the lowest setting the pump creates too strong a current for my fish which is pretty common for betta fish who have very large fins and usually like to swim at the surface. because of that I turn on the filter for about 10 minutes a day just to get the water moving and give my fish some exercise and am currently working on modifying the output flow to make it more comfortable for my fish for longer periods of a time. but even with only being on for 10 minutes a day this system works wonderfully and I can tell a difference in the tank which is why i'm giving it 5 stars.
Pros: easy to clean, works great, easy to install
-1point
1of 3voted this as helpful.
Review 7 for Fluval(r) Underwater Filter
Overall rating 
5 / 5
5 / 5 21 reviews

great product

October 9, 2013
by rebeccca
fromcolorado
What is your gender?F
How many pets do you have?5 or more
How often do you shop at PetSmart?Monthly
Performance 
5 / 5
5 / 5 21 reviews
Quality 
5 / 5
5 / 5 21 reviews
Ease of Use 
5 / 5
5 / 5 21 reviews
I originally bought the Fluval U4 to use in my turtle terrarium. However, because I was only partially filling the tank I decided the U4 would be a little to big and went with the U3. I have been very pleased with the fluval U3! turtles are messy and I also have some fish in the tank- but my water remains crystal clear! My petsmart did not carry the U4 in stores, so I had to order it online. They gave me no hassle what so ever about returning it in store vs. shipping it back when I decided to go with the U3 instead. I was overall very pleased with my product and shopping experience.
Pros: works great, easy to install
+5points
5of 5voted this as helpful.
Review 8 for Fluval(r) Underwater Filter
Overall rating 
5 / 5
5 / 5 21 reviews

Amazed

May 6, 2013
by Maxtor
fromMilford, DE
What is your gender?M
How many pets do you have?5 or more
How often do you shop at PetSmart?Monthly
Performance 
5 / 5
5 / 5 21 reviews
Quality 
5 / 5
5 / 5 21 reviews
Ease of Use 
5 / 5
5 / 5 21 reviews
Was looking for a filter for a new 29gal tank setup. Looked at reviews for the Fluval U3 and thought this might be a good choice. Purchased and set up in my existing 20gal to let it cycle there before starting the new tank. My existing 20 had a Whisper 20 in it which I thought did a good job.....boy was I wrong! The U3 had the water crystal clear in no time. Puts my old one to shame. Will definitely be purchasing a U2 to replace that old filter!!! U3 is simple to begin using and feels well built. Filter media changes are going to be super easy. AWESOME AWESOME AWESOME!!!!
Pros: works great, easy to install
+5points
5of 5voted this as helpful.
Review 9 for Fluval(r) Underwater Filter
Overall rating 
5 / 5
5 / 5 21 reviews

Crystal clear

April 14, 2013
by mestrass
fromchicago suburbs
What is your gender?F
How many pets do you have?5 or more
How often do you shop at PetSmart?Monthly
Performance 
5 / 5
5 / 5 21 reviews
Quality 
5 / 5
5 / 5 21 reviews
Ease of Use 
5 / 5
5 / 5 21 reviews
I started a 55 gallon premolded pond with quite a few messy goldfish. The tank went for about 4 days without a filter and got very cloudy. I knew the ammonia levels had to be elevated and there was alot of waste. Within 15 minutes of plugging in the filter, the water was already crystal clear and the flow is adjustable. It is easily hidden and absolutely silent.
For beginners, i cannot recommend a better, more affordable filter. Easy to set up and well worth the price. I have had aquariums my whole life and have spend much more on much less efficient equipment.
Pros: works great, easy to install, easy to clean
+7points
7of 7voted this as helpful.
Review 10 for Fluval(r) Underwater Filter
Overall rating 
5 / 5
5 / 5 21 reviews

Great filter!

March 7, 2013
by MSally88
fromVirginia
How often do you shop at PetSmart?Weekly
Great warranty! I use this in an African Leaf Fish tank and I love it.. it's much quieter than the typical filters that hang on the back of the tank and does a great job of circulating the enitre tank.
+1point
1of 1voted this as helpful.
Review 11 for Fluval(r) Underwater Filter
Overall rating 
2 / 5
2 / 5 21 reviews

Worked great... until it broke after 5 months.

February 3, 2013
by EnoughCats
fromFredericton, NB
What is your gender?F
How many pets do you have?5 or more
How often do you shop at PetSmart?Weekly
Performance 
5 / 5
5 / 5 21 reviews
Quality 
2 / 5
2 / 5 21 reviews
Ease of Use 
4 / 5
4 / 5 21 reviews
I bought the U3 and was initially very impressed with it. I loved how quiet it was and that it would not burn out after a power outage because you didn't have to prime it. It did it's job of keeping the water clean and clear. On the downside it was quite bulky and took up a fair portion of my tank. My U3 broke after only 5 months of use. I maintained the unit well and changed media regularly. If it hadn't quit on me I would have given it 4 stars.
Pros: easy to clean
Cons: didn't work
+2points
3of 4voted this as helpful.
Review 12 for Fluval(r) Underwater Filter
Overall rating 
4 / 5
4 / 5 21 reviews

Surge Protector a MUST...

December 28, 2012
by AnmlLvr13
fromNorristown, PA
What is your gender?F
How many pets do you have?5 or more
How often do you shop at PetSmart?Weekly
Performance 
4 / 5
4 / 5 21 reviews
Quality 
3 / 5
3 / 5 21 reviews
Ease of Use 
4 / 5
4 / 5 21 reviews
I recently acquired two turtles and this filter has been amazing. Easy to use, quite and the water was crystal clear... until a brief power outage one night. The filter's motor is shot. I would still recommend this filter to anyone, as long as a surge protector is used.
Pros: easy to install, easy to clean
+4points
4of 4voted this as helpful.
Review 13 for Fluval(r) Underwater Filter
Overall rating 
5 / 5
5 / 5 21 reviews

The U2 is just amazing.

December 25, 2012
by AppleGeek
fromNorfolk Virginia
What is your gender?M
How many pets do you have?5 or more
How often do you shop at PetSmart?Weekly
Performance 
5 / 5
5 / 5 21 reviews
Quality 
5 / 5
5 / 5 21 reviews
Ease of Use 
5 / 5
5 / 5 21 reviews
I purchased a 10 gallon kit 6 months ago that came with another HOB filter that was so loud, and unreliable. I picked up a U2 about 2 months ago, and I was amazed, a few hours after setting it up and putting it in my tank, it cleared the water and it made everything look great in my tank. about a week ago, I removed one of the carbon pads, and put a filter bag with Seachem Purigen in it, it cleared the water even more, and now it looks like my fish are floating on air. I love it.
Pros: easy to clean, works great, easy to install
+4points
4of 4voted this as helpful.
Review 14 for Fluval(r) Underwater Filter
Overall rating 
5 / 5
5 / 5 21 reviews

Awesome Filter

May 24, 2012
by Lunarcat13
fromCape May, New Jersey
What is your gender?F
How many pets do you have?5 or more
How often do you shop at PetSmart?Weekly
We have a 60 gallon tank with 2 turtles and quite a few fish. We got the U4 filter when we upgraded from a smaller tank to this one. It was recommended to me by someone so i decided to try it. Its quiet, powerful and can take a beating basically. We fell behind in our cleaning duties and the filter still kept the water fairly clear and after the cleaning when we stirred up all the stuff on the bottom and out of the plants with in 30 minutes tops the water was crystal clear again like we just put the tank together on the first day. I would recommend this to anyone with fish and/or aquatic reptiles! In fact I'm thinking about getting the U3 for our smaller tank to replace the one we have on there now.
+4points
4of 4voted this as helpful.
Review 15 for Fluval(r) Underwater Filter
Overall rating 
3 / 5
3 / 5 21 reviews

Good But......

April 2, 2012
by John60
fromSt. Charles, Mo
What is your gender?M
How many pets do you have?5 or more
How often do you shop at PetSmart?Weekly
A good filter overall but the ceramic rings they give you are enough to fill the cage only half way. For the price you pay for the filter.....need I say? Sometimes you don't get what you pay for.
-3points
4of 11voted this as helpful.
Review 16 for Fluval(r) Underwater Filter
Overall rating 
5 / 5
5 / 5 21 reviews

Quiet, and clean

March 13, 2012
by rlar422
fromCT
What is your gender?F
How many pets do you have?5 or more
How often do you shop at PetSmart?A few times a year
I have two of Fluval underwater filters, the U3 in my 29 gallon tank and the U1 in my 10 gallon tank, and I love them! They are so quiet and do an excellent job keeping the water clean. My U3 I have towards on side of my tank with it on the top spout on at an angle so it pushes the feces from my large pleco to be sucked into the filter. I have the U1 at the top with the air setting on, which is quiet as well and it keeps the tank aerated and clean! I love them!
+6points
6of 6voted this as helpful.
Review 17 for Fluval(r) Underwater Filter
Overall rating 
5 / 5
5 / 5 21 reviews

Fantastic, QUIET filter

February 15, 2012
by Trace0306
fromSoutheastern, CT
What is your gender?F
How many pets do you have?5 or more
How often do you shop at PetSmart?Weekly
Thank goodness for great online reviews, because that's how we came to find this filter. We had a Marineland Penguin BioWheel that spontaneously stopped working after 2ish months. We got this Fluval U3 filter (29 gal tank) and installed it (5 min max!), within a couple hours, the tank looked as if we hadn't had a dead filter for a week, and the next morning, the water is completely clear. We use the airation option, and it doesn't sound like a running waterfall like the BioWheel. It'll take some time to see how it works out, but I have much higher hopes for this filter than the last.
+3points
3of 3voted this as helpful.
Review 18 for Fluval(r) Underwater Filter
Overall rating 
5 / 5
5 / 5 21 reviews

The most amazing thing ever!

January 14, 2012
by Lina1234
fromTexas
What is your gender?F
How many pets do you have?5 or more
How often do you shop at PetSmart?Monthly
I bought the Fluval u1 for my ten gallon tank and it is amazing. The filter part is wonderful but what i love is that it is 100% quiet. In my starter kit i had a top fin filter and it was horrible. It kept vibrating and the hum was so annoying. It was in my room so it had to be dead silent. I did some research and i found this. I hooked it up ten minutes ago and i cant even hear it. I had to stick my finger in front of it to see if it was on. If you want a quiet filter, i highly recommend this. It's worth the money!!! Love it!
+5points
5of 5voted this as helpful.
Review 19 for Fluval(r) Underwater Filter
Overall rating 
5 / 5
5 / 5 21 reviews

Fantastic Filter!

March 15, 2011
by Abernathy
fromPortland, OR
What is your gender?F
How many pets do you have?5 or more
How often do you shop at PetSmart?Monthly
Performance 
5 / 5
5 / 5 21 reviews
Quality 
5 / 5
5 / 5 21 reviews
Ease of Use 
5 / 5
5 / 5 21 reviews
I purchased this filter when I set up my 46 gallon tank. It's really easy to set up and to use, and I love how it has the 3 different flow settings. My fish seem to prefer the water flowing across the surface, with bubbles, but during feeding, I change the flow to the middle. Just turn a dial. Changing the foam and everything inside is really, really easy. The filter also provides a hiding place for my upside-down catfish, and occasionally a tiger barb or a gourami will hang out under it too. Overall, FABULOUS product!
Pros: easy to clean, easy to install, works great
+7points
7of 7voted this as helpful.
Review 20 for Fluval(r) Underwater Filter
Overall rating 
5 / 5
5 / 5 21 reviews

Found a winner!

March 15, 2011
by jessicabc
fromBC, Canada
What is your gender?F
How many pets do you have?4
How often do you shop at PetSmart?Monthly
Performance 
5 / 5
5 / 5 21 reviews
Quality 
5 / 5
5 / 5 21 reviews
Ease of Use 
4 / 5
4 / 5 21 reviews
I'm so happy I decided to get this filter. I went through 3 other HOB ones before it, they were all way too noisy (and one was too big to even fit under my aquarium's hood). This one is super quiet. I haven't decided if I'll use the venturi valve for oxygenating the water or not, the bubbles are pretty quiet though so I'll give it a try. My aquarium is in my room so it definitely needs to be quiet. It took a little fiddling to get the level of the filter and the valve just right for the small amount of bubbles, which isn't a big deal, just need to find the right balance for what you want.
I got the U2 for my 23 gallon tank and I think it should be enough filtration. I was going to get the U3 but the size definitely put me off. The size of the U2 is fine though, it isn't too bulky and doesn't hog too much space (I have it in one corner of the tank just below the surface).
It was pretty easy to set up and looks like changing the filter bits will be easy enough as well. Doesn't seem complicated to me.
I really recommend this filter. Forget AquaClear.
Pros: easy to clean, easy to install, works great
+6points
8of 10voted this as helpful.
1 2 next