Fluval discount U4 Underwater Filter, outlet sale Freshwater and Saltwater Aquarium Filter, A480 online sale

Fluval discount U4 Underwater Filter, outlet sale Freshwater and Saltwater Aquarium Filter, A480 online sale

Fluval discount U4 Underwater Filter, outlet sale Freshwater and Saltwater Aquarium Filter, A480 online sale
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Breed Recommendation
Medium
Brand
Fluval
Recommended Uses For Product
Aquarium filter
Indoor/Outdoor Usage
Indoor
Is Waterproof
True

Small cosmetic imperfection on top, front or sides of item. Small cosmetic imperfection on interior of item. Item will come in original packaging. Packaging will be damaged.
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Breed Recommendation
Medium
Brand
Fluval
Recommended Uses For Product
Aquarium filter
Indoor/Outdoor Usage
Indoor
Is Waterproof
True
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This item Fluval U4 Underwater Filter, F... Fluval U Series Underwater Fil... Fluval U4 Poly-Carb Cartridge,... Fluval U4 Bio-Foam Pad, Replac...
Rating 4.5 out of 5 stars
1549 reviews
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Price $73.06 $36.99 $5.99 $5.79
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Value for money 4.2 4.0 4.9 4.5
Suction power 4.4 4.2 5.0
Easy to clean 4.1 4.0
Noise level 4.5 4.5
Item Dimensions 4.6 x 5.2 x 14 inches 12 x 6 x 5 inches 0.59 x 2.36 x 3.38 inches 2.7 x 2.7 x 11 inches
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From the manufacturer

Fluval Underwater Filter

Offering outstanding 3-stage filtration, increased water movement and vital aeration, Fluval U-Series internal filters are the perfect solution where external filtration is not possible.

  • Designed for aquarium up to 65 gallons
  • Use as a primary filter for smaller aquariums, or supplementary filter for larger aquariums
  • Position horizontally for shallow tanks, larger tanks with low water levels, or to create a decorative waterfall feature
  • Position vertically against aquarium wall to create currents or customized flow patterns
  • Convenient flip-top lid allows for quick and easy access to filter cartridge for maintenance or replacement
  • Adjustable 3-way flow control – Top Output for circulation and oxygenation, Integrated Spray Bar for a gentle even flow, and Bottom Output for deepwater agitation

Description

Fluval U4 Underwater Filter is ideal for use in all aquarium or reptile environments. Use the underwater filter as a primary filter in smaller aquariums or as a supplementary filter for larger aquariums. Fluval Underwater Filters with three-stage filtration are ideal for use in fresh, marine or reptile environments, and are also great for tanks with low water levels. Three-stage filtration with BioMax for superior aquarium water quality, flip-top access for quick and easy cartridge replacement, and three-way flow control make the new Fluval U Series the benchmark in underwater filtration. Stage 1 foam removes large particles. In stage 2, the poly/carbon cartridge traps fine debris, improves water clarity and removes impurities. In stage 3, BioMax provides optimal biological filtration efficiency.

For more fish tank accessories, check out other Fluval products including aquarium filters, aquarium heaters, aquarium air pumps, aquarium lights, aquarium rocks, aquarium thermometers, and aquarium stands. Fluval has a wide variety of products that are perfect for your pet fish to enjoy in any large fish tank, small fish tank, saltwater tank or freshwater tank. Fluval broke onto the aquatic scene in 1975 by introducing the world’s first 3-stage filter with synchronous motor technology – a breakthrough that is still applied in the industry today. Since then, Fluval has built a legacy around this pioneering spirit, relentlessly adapting in a changing world to launch innovative aquarium products that remain at the forefront of technology, and which set the bar in quality, style and functionality. Fluval’s mission is not just about building products that mimic the natural world, but inspiring aquarists of all skill levels to enjoy and respect the hobby for generations to come.

Features & details

Features

  • Use as a primary filter for smaller aquariums, or supplementary filter for larger aquariums
  • Sleek design with easy grip water control panel and redesigned media cartridge to trap more debris
  • Convenient flip-top lid allows for quick and easy access to filter cartridge for maintenance or replacement
  • Position horizontally for shallow tanks, larger tanks with low water levels, or to create a decorative waterfall feature or vertically against aquarium wall to create currents or customized flow patterns
  • Designed for freshwater, saltwater and reptile environments up to 65 gallons

Product information

    Additional Information

  • ASIN: B001XRXY1G
  • Customer Reviews: 4.5 out of 5 stars 1,549Reviews
  • Best Sellers Rank:
    #27,933 in Pet Supplies (See Top 100 in Pet Supplies)
    #331 in Aquarium Filter Accessories
  • Date First Available: August 19, 2004

Important information

Directions :

Follow instuctions on product

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Product guides and documents

Product Documentation (PDF)
User Manual (PDF)
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Customer Questions

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Q: Currently have a 10gallon but will upgrade shortly to a 30ish for a yellow eared turtle. …

A: Mine is laying on the bottom of my tank and i have never had it sitting upright. I can tel…

Maghan Wilson | 4 years ago

Q: Does the U4 filter have space to add activated carbon pellets?

A: Yes it can, in the center of the filter there a removeable plastic cage. I put a small Che…

David M. Davidson | 8 years ago

Q: Do all 3 outputs work at the same time?

A: No. There is a dial to choose one at a time.

Leon Qubick | 4 years ago

Q: Does it have to be totally submerged to work? Thanks

A: You have to make sure the little vents on the side are submerged, so about a centimeter ca…

Chantal | 2 years ago

Customer reviews

4.5 out of 54.5 out of 5
1,549 global ratings

Reviews with videos

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Top reviews from the United States

TangieTP
4.0 out of 5 starsVerified Purchase
Confused by bad reviews
Reviewed in the United States on May 9, 2019
I have been running this filter for several months in my 45 gallon aquarium. Two things other reviewers are commenting on have me confused. 1) This filter is NOT noisy. I can''t hear it. At all. Compared to other filters out there, the sound factor is negligible... so unless... See more
I have been running this filter for several months in my 45 gallon aquarium. Two things other reviewers are commenting on have me confused. 1) This filter is NOT noisy. I can''t hear it. At all. Compared to other filters out there, the sound factor is negligible... so unless you are deliberately pressing your ear up to the thing, there''s nothing to hear. 2) On shrimp/fry. I have red cherry shrimp that breed like rabbits and the fry INTENTIONALLY hang out on the slots between the outside and the interior foam. They don''t get "sucked in" or stuck... they go there and feed and swim away. It doesn''t pull them into the filter, the suction is efficient but not that crazy and the foam pad keeps them from injury. They just like to eat off of it. Maybe previous reviewers had some freak thing happen, but I have not modified this in any way to be safe for my little shrimp. The only reason I have docked this by one star is because the back suction/mount annoys me because when I go to rinse out the media, it always pops forward and gets messed up and I have to dink with it to remount it and not squish any curious fish or shrimp behind it when I pop it back into place. Just takes a little extra fidgeting, but in the scheme of things, not a big deal. Overall, a great filter. I far prefer it to Hobs. And I kind of hate canister filters for being loud and cumbersome. This is a nice alternative.
71 people found this helpful
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goat8485
5.0 out of 5 starsVerified Purchase
Quiet filter and Great for Turtles!
Reviewed in the United States on October 13, 2014
FINALLY a filter that works for turtles. This filter can mount sideways, which is great news for turtle owners who only fill the tank halfway to allow room for a turtle basking platform. Most filters are designed to draw water from the very top of a full tank. This filter... See more
FINALLY a filter that works for turtles. This filter can mount sideways, which is great news for turtle owners who only fill the tank halfway to allow room for a turtle basking platform. Most filters are designed to draw water from the very top of a full tank. This filter can be mounted either vertically or horizontally to accommodate a lower water level.

This is also the quietest filter I have ever owned. The entire filtration process occurs below the water level, so there is no running water sound, only the soft hum of the impeller drawing water into the unit. Also, all water says inside the tank, so there is no concern with leaks or broken hoses as you might expect from an external canister filter.

I have this filter set up in a 40 gallon tank with one medium sized red-eared slider. It does a great job of keeping the water clear, and it is easy to maintain. With more turtles or a larger tank, I would recommend using more than one U4 filter to ensure enough filtration power.

Overall, I am very happy with this filter and would definitely recommend it to fellow turtle owners.
103 people found this helpful
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Me
5.0 out of 5 starsVerified Purchase
Best turtle filter evah!
Reviewed in the United States on May 10, 2021
Turtle owner here.. and if you know, they are very rowdy and extremely dirty.. they absolutey trash their water. And all the other filters are.so loud we had to shut them off constantly.. This filter is just what I was hoping for! It''s very effective, and cleans out the... See more
Turtle owner here.. and if you know, they are very rowdy and extremely dirty.. they absolutey trash their water. And all the other filters are.so loud we had to shut them off constantly.. This filter is just what I was hoping for! It''s very effective, and cleans out the water fast, and it''s really quiet!! It also has a built in aerator so we could take out the bubble wall.. and the water crystal clear. The filter comes out and disassembles quickly for easy cleaning and makes the water changes just some much better. I''ve been looking for a good quiet filter for a while now and this is definitely worth the purchase. Highly recommend!
8 people found this helpful
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Frank
4.0 out of 5 starsVerified Purchase
The U4 filters the water well and has good flow, but it has two main flaws
Reviewed in the United States on April 27, 2016
The U4 filters the water well. Its silent and has good flow, but it has two main flaws. The first one is too much dirt drops out of the filter trying to get it out of the tank to clean it. I figured out a way around this by placing the U4 in a large filter sock before... See more
The U4 filters the water well. Its silent and has good flow, but it has two main flaws. The first one is too much dirt drops out of the filter trying to get it out of the tank to clean it. I figured out a way around this by placing the U4 in a large filter sock before lifting it out of the tank.The second issue is that the sponge and carbon filter pad compartment should be enclosed so you can put whatever media you want in it just like the center bio compartment. The design of the outer compartments force you to use Fluval''s weak carbon pad instead of being able to jam a bag of carbon in it or a purigen pouch if you wanted. I''ve gotten around this by using generic non-carbon fine filter pads along with the coarse sponge that comes with the U4 in the outer compartments and placing a chemi-pure blue nano pouch in the center compartment with the Fluval bio-max biological media.
29 people found this helpful
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Dodge charger shi fu
5.0 out of 5 starsVerified Purchase
55g submersible filter in live planted
Reviewed in the United States on December 6, 2020
I purchased this item becausr I''ve been struggling with my cascade canister filter. My first impression is that it is very strong but also dead silent. It is unlike anything else I''ve ever had. A test was ran using my new submersible filter alone and... See more
I purchased this item becausr I''ve been struggling with my cascade canister filter.

My first impression is that it is very strong but also dead silent. It is unlike anything else I''ve ever had.

A test was ran using my new submersible filter alone and then later with my cascade canister.

The cascade actually makes my water quality worse even if it had established or new media in it.

Ive added a bunch of various filters to the cascade over the years but no matter what I did, it still seemed to have alot of hazy cloudy green water - no chemicals helped either.

Eventually, ill just buy another submersible filter and stay away from the canister filters.

Update: I''ve thrown my canister filter away and only use the submersible filter, it''s much better.
2 people found this helpful
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Diane Perera
5.0 out of 5 starsVerified Purchase
Great filter for the price!!
Reviewed in the United States on June 27, 2019
This cleared up my turtle’s 40 gallon tank immediately. I had a Fluval 406 that started leaking so I bought this as a replacement. So far so good. In the past I had a Fluval submersible filter that lasted over 10 years. I am hoping to have similar luck. (Unlike the bad luck... See more
This cleared up my turtle’s 40 gallon tank immediately. I had a Fluval 406 that started leaking so I bought this as a replacement. So far so good. In the past I had a Fluval submersible filter that lasted over 10 years. I am hoping to have similar luck. (Unlike the bad luck I had with the Fluval external 406 canister filters). I think for smaller tanks this is the way to go. Just plug and play!!!!
6 people found this helpful
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melissa richardson
1.0 out of 5 starsVerified Purchase
Strong, silent, fantastic!!
Reviewed in the United States on March 4, 2020
The filter was just setup this week and already has been fantastic! The 40 gallon tank cleared up within 15 minutes of install. The best part? Silence. Absolute silence. My turtles knock on it and climb it and it stays put. I will try to update in a few months after using... See more
The filter was just setup this week and already has been fantastic! The 40 gallon tank cleared up within 15 minutes of install. The best part? Silence. Absolute silence. My turtles knock on it and climb it and it stays put. I will try to update in a few months after using it for awhile but so far, amazing.

UPDATE: Broke after 3 months, almost to the day.
4 people found this helpful
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Aerith Gainsborough
1.0 out of 5 starsVerified Purchase
KILLS FISH. They will become stuck behind the mount!
Reviewed in the United States on August 23, 2019
Was working wonderfully, I actually loved this filter until I realized fish were starting to get stuck behind it. Luckily I spotted one of my fish behind the mount, and was able to save him. But here it is today, and my beautiful koi betta found his way behind it, and I was... See more
Was working wonderfully, I actually loved this filter until I realized fish were starting to get stuck behind it. Luckily I spotted one of my fish behind the mount, and was able to save him. But here it is today, and my beautiful koi betta found his way behind it, and I was not so lucky to see and save him. He is now gone because of this filters safety failure with gaps behind the filter mount and filter itself. I would not buy this until they come up with a safer means of mounting this unit without leaving gaps. I can''t imagine how much my baby suffered trying to get out and get air. This is just horrible...
3 people found this helpful
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Top reviews from other countries

Paul J Davies
5.0 out of 5 starsVerified Purchase
So Much better than my old filter.
Reviewed in the United Kingdom on April 15, 2020
The difference this filter made to my tank is night and day, my old Aquael Turbo filter did an ok Job I guess, until it came time to clean it, having the sponge exposed and sitting below the pump was unsightly for me, but when taking out to clean it all the captured crap...See more
The difference this filter made to my tank is night and day, my old Aquael Turbo filter did an ok Job I guess, until it came time to clean it, having the sponge exposed and sitting below the pump was unsightly for me, but when taking out to clean it all the captured crap just dropped right back into the tank, was never happy with it, Now lets talk about the Fluval U4 !! …. well its like trading in a mini for a Mercedes … the 3 separate filters are easily pulled from the housing without having to dismantle the pump or remove it from the tank, ingenious design. Very powerful for my 200 Litre tank and I can easily change the filtration method by the simple twist of the control, again ingenious. One point I did notice however, and this is minor and easily sorted, after cleaning the filter pads and replacing I noticed the filter was noisier, it sounded like air was trapped within the filter housing and causing a gurgling sound, to fix all I did was lift the 3 filter compartments and drop them back down, this cleared the noise instantly, and its worth noting that the Fluval U4 runs full blast with silence. My tank water is now crystal clear with a monthly rinse out ( with tank water ) of the sponges and pads. Fully recommended. !!!
9 people found this helpful
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Glenn Perry
5.0 out of 5 starsVerified Purchase
Fantastic filter for my 80l tank
Reviewed in the United Kingdom on March 7, 2018
I bought this for my 80l tank as my U3 started to fail. I hoped it wouldn''t be too powerful for my tank and it isn''t. It works great and left the water crystal clear within a few hours (I''d cleaned the tank just before I installed it). I followed the instructions to the...See more
I bought this for my 80l tank as my U3 started to fail. I hoped it wouldn''t be too powerful for my tank and it isn''t. It works great and left the water crystal clear within a few hours (I''d cleaned the tank just before I installed it). I followed the instructions to the latter and all worked perfectly and lovely and quiet. Mine is just below water level and makes the plants (fake) sway which is nice. Just enough agitation for my clown loaches to enjoy. I''ve not tried the middle or lower outlets so can''t comment on them. I just transferred the bio stuff from my old U3 into this one and all is good. I''m hoping I won''t have to clean the filter as much as the U3. All in all, physically it''s probably just a bit big for my tank but power wise it''s perfect. I had to do some research as I noticed the blue baskets that hold the filters half of the holes were covered up which I thought was odd but apparently it''s a new design to trap more debris. For the price this filter is fantastic and should need less cleaning (for my 80l tank), although I also use a water conditioner.
11 people found this helpful
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Jacob L.
5.0 out of 5 starsVerified Purchase
I wouldnt use anything else
Reviewed in the United Kingdom on May 20, 2018
I have one of these in a 180l tank and another in a 260l tank and it works great in both. I like I can change the flow from the top to the bottom. The removable cartridges are a big improvement and makes it easier to clean. I have never found another internal filter this...See more
I have one of these in a 180l tank and another in a 260l tank and it works great in both. I like I can change the flow from the top to the bottom. The removable cartridges are a big improvement and makes it easier to clean. I have never found another internal filter this good and I prefer it over budget external ones.
10 people found this helpful
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Voice of Reason
5.0 out of 5 starsVerified Purchase
Superb
Reviewed in the United Kingdom on October 11, 2013
This is a replacement for an Eheim Powerflow 240 which I have got to say was a huge dissapointment so was sent back through the Amazon 30 day return policy. This filter is far superior to the previous product in several ways. Firstly the media changing is a lot easier and...See more
This is a replacement for an Eheim Powerflow 240 which I have got to say was a huge dissapointment so was sent back through the Amazon 30 day return policy. This filter is far superior to the previous product in several ways. Firstly the media changing is a lot easier and can be done with the unit in situ. The mechanical filtration area is a lot bigger with the biological compartment a bit smaller which makes more sense. A very nice feature is the choice of outflow from either the top/bottom jet or middle built in trickle bar. The outflow is also a lot more powerful which is reassuring. The only negative is the bio media supplied is very meagre so you may want to buy extra to fill the basket! It seems reasonably well made and carries a 3 year warranty in the UK so gives added peace of mind. Highly recommended. L
28 people found this helpful
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Andy
3.0 out of 5 starsVerified Purchase
Works OK but expected better
Reviewed in the United Kingdom on May 23, 2019
Bought to replace a JBL CristalProfi on the strentgh of other reviews on here. It''s being used on a Fluval Roma 125l tank, which in theory this U4 filter should be more than enough to handle. Whilst installing and cleaning is straight forward and inexpensive (replacement...See more
Bought to replace a JBL CristalProfi on the strentgh of other reviews on here. It''s being used on a Fluval Roma 125l tank, which in theory this U4 filter should be more than enough to handle. Whilst installing and cleaning is straight forward and inexpensive (replacement filters are cheap and easy to come by), I''ve been disappointed with the water clarity of the tank, despite regular water changes. Using on the middle or bottom filter settings the tank clouded up relatively quickly, so I''ve always had to use on the top and most powerful setting. More recently the filter completely stopped and needed a jolt to get it running again. Whilst it does an OK job my previous JBL filter produced clearer water and for longer, but was more time consuming to replace the filters and media. Will look into upgrading to an external filter next time.
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Fluval Underwater Filter

Offering outstanding 3-stage filtration, increased water movement and vital aeration, Fluval U-Series internal filters are the perfect solution where external filtration is not possible.

Description

Fluval U4 Underwater Filter is ideal for use in all aquarium or reptile environments. Use the underwater filter as a primary filter in smaller aquariums or as a supplementary filter for larger aquariums. Fluval Underwater Filters with three-stage filtration are ideal for use in fresh, marine or reptile environments, and are also great for tanks with low water levels. Three-stage filtration with BioMax for superior aquarium water quality, flip-top access for quick and easy cartridge replacement, and three-way flow control make the new Fluval U Series the benchmark in underwater filtration. Stage 1 foam removes large particles. In stage 2, the poly/carbon cartridge traps fine debris, improves water clarity and removes impurities. In stage 3, BioMax provides optimal biological filtration efficiency.

For more fish tank accessories, check out other Fluval products including aquarium filters, aquarium heaters, aquarium air pumps, aquarium lights, aquarium rocks, aquarium thermometers, and aquarium stands. Fluval has a wide variety of products that are perfect for your pet fish to enjoy in any large fish tank, small fish tank, saltwater tank or freshwater tank. Fluval broke onto the aquatic scene in 1975 by introducing the world’s first 3-stage filter with synchronous motor technology – a breakthrough that is still applied in the industry today. Since then, Fluval has built a legacy around this pioneering spirit, relentlessly adapting in a changing world to launch innovative aquarium products that remain at the forefront of technology, and which set the bar in quality, style and functionality. Fluval’s mission is not just about building products that mimic the natural world, but inspiring aquarists of all skill levels to enjoy and respect the hobby for generations to come.

Features & details

Features

  • Use as a primary filter for smaller aquariums, or supplementary filter for larger aquariums
  • Sleek design with easy grip water control panel and redesigned media cartridge to trap more debris
  • Convenient flip-top lid allows for quick and easy access to filter cartridge for maintenance or replacement
  • Position horizontally for shallow tanks, larger tanks with low water levels, or to create a decorative waterfall feature or vertically against aquarium wall to create currents or customized flow patterns
  • Designed for freshwater, saltwater and reptile environments up to 65 gallons

Product information

    Additional Information

  • ASIN: B001XRXY1G
  • Customer Reviews: 4.5 out of 5 stars 1,549Reviews
  • Best Sellers Rank:
    #27,933 in Pet Supplies (See Top 100 in Pet Supplies)
    #331 in Aquarium Filter Accessories
  • Date First Available: August 19, 2004

Important information

Directions :

Follow instuctions on product

Brief content visible, double tap to read full content.
Full content visible, double tap to read brief content.

Product guides and documents

Product Documentation (PDF)
User Manual (PDF)
Brief content visible, double tap to read full content.
Full content visible, double tap to read brief content.

Related posts

Customer Questions

Sorry, we were unable to perform your search at this time.

There was a problem completing your request. Please try again later.

Don''t see the answer you''re looking for?

Your question might be answered by sellers, manufacturers, or customers who bought this product.

Please make sure that you are posting in the form of a question.

Please enter a question.

Q: Currently have a 10gallon but will upgrade shortly to a 30ish for a yellow eared turtle. …

A: Mine is laying on the bottom of my tank and i have never had it sitting upright. I can tel…

Maghan Wilson | 4 years ago

Q: Does the U4 filter have space to add activated carbon pellets?

A: Yes it can, in the center of the filter there a removeable plastic cage. I put a small Che…

David M. Davidson | 8 years ago

Q: Do all 3 outputs work at the same time?

A: No. There is a dial to choose one at a time.

Leon Qubick | 4 years ago

Q: Does it have to be totally submerged to work? Thanks

A: You have to make sure the little vents on the side are submerged, so about a centimeter ca…

Chantal | 2 years ago

Customer reviews

4.5 out of 54.5 out of 5
1,549 global ratings

Reviews with videos

Reviews with images

Top reviews from the United States

TangieTP
4.0 out of 5 starsVerified Purchase
Confused by bad reviews
Reviewed in the United States on May 9, 2019
I have been running this filter for several months in my 45 gallon aquarium. Two things other reviewers are commenting on have me confused. 1) This filter is NOT noisy. I can''t hear it. At all. Compared to other filters out there, the sound factor is negligible... so unless... See more
I have been running this filter for several months in my 45 gallon aquarium. Two things other reviewers are commenting on have me confused. 1) This filter is NOT noisy. I can''t hear it. At all. Compared to other filters out there, the sound factor is negligible... so unless you are deliberately pressing your ear up to the thing, there''s nothing to hear. 2) On shrimp/fry. I have red cherry shrimp that breed like rabbits and the fry INTENTIONALLY hang out on the slots between the outside and the interior foam. They don''t get "sucked in" or stuck... they go there and feed and swim away. It doesn''t pull them into the filter, the suction is efficient but not that crazy and the foam pad keeps them from injury. They just like to eat off of it. Maybe previous reviewers had some freak thing happen, but I have not modified this in any way to be safe for my little shrimp. The only reason I have docked this by one star is because the back suction/mount annoys me because when I go to rinse out the media, it always pops forward and gets messed up and I have to dink with it to remount it and not squish any curious fish or shrimp behind it when I pop it back into place. Just takes a little extra fidgeting, but in the scheme of things, not a big deal. Overall, a great filter. I far prefer it to Hobs. And I kind of hate canister filters for being loud and cumbersome. This is a nice alternative.
71 people found this helpful
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goat8485
5.0 out of 5 starsVerified Purchase
Quiet filter and Great for Turtles!
Reviewed in the United States on October 13, 2014
FINALLY a filter that works for turtles. This filter can mount sideways, which is great news for turtle owners who only fill the tank halfway to allow room for a turtle basking platform. Most filters are designed to draw water from the very top of a full tank. This filter... See more
FINALLY a filter that works for turtles. This filter can mount sideways, which is great news for turtle owners who only fill the tank halfway to allow room for a turtle basking platform. Most filters are designed to draw water from the very top of a full tank. This filter can be mounted either vertically or horizontally to accommodate a lower water level.

This is also the quietest filter I have ever owned. The entire filtration process occurs below the water level, so there is no running water sound, only the soft hum of the impeller drawing water into the unit. Also, all water says inside the tank, so there is no concern with leaks or broken hoses as you might expect from an external canister filter.

I have this filter set up in a 40 gallon tank with one medium sized red-eared slider. It does a great job of keeping the water clear, and it is easy to maintain. With more turtles or a larger tank, I would recommend using more than one U4 filter to ensure enough filtration power.

Overall, I am very happy with this filter and would definitely recommend it to fellow turtle owners.
103 people found this helpful
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Me
5.0 out of 5 starsVerified Purchase
Best turtle filter evah!
Reviewed in the United States on May 10, 2021
Turtle owner here.. and if you know, they are very rowdy and extremely dirty.. they absolutey trash their water. And all the other filters are.so loud we had to shut them off constantly.. This filter is just what I was hoping for! It''s very effective, and cleans out the... See more
Turtle owner here.. and if you know, they are very rowdy and extremely dirty.. they absolutey trash their water. And all the other filters are.so loud we had to shut them off constantly.. This filter is just what I was hoping for! It''s very effective, and cleans out the water fast, and it''s really quiet!! It also has a built in aerator so we could take out the bubble wall.. and the water crystal clear. The filter comes out and disassembles quickly for easy cleaning and makes the water changes just some much better. I''ve been looking for a good quiet filter for a while now and this is definitely worth the purchase. Highly recommend!
8 people found this helpful
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Frank
4.0 out of 5 starsVerified Purchase
The U4 filters the water well and has good flow, but it has two main flaws
Reviewed in the United States on April 27, 2016
The U4 filters the water well. Its silent and has good flow, but it has two main flaws. The first one is too much dirt drops out of the filter trying to get it out of the tank to clean it. I figured out a way around this by placing the U4 in a large filter sock before... See more
The U4 filters the water well. Its silent and has good flow, but it has two main flaws. The first one is too much dirt drops out of the filter trying to get it out of the tank to clean it. I figured out a way around this by placing the U4 in a large filter sock before lifting it out of the tank.The second issue is that the sponge and carbon filter pad compartment should be enclosed so you can put whatever media you want in it just like the center bio compartment. The design of the outer compartments force you to use Fluval''s weak carbon pad instead of being able to jam a bag of carbon in it or a purigen pouch if you wanted. I''ve gotten around this by using generic non-carbon fine filter pads along with the coarse sponge that comes with the U4 in the outer compartments and placing a chemi-pure blue nano pouch in the center compartment with the Fluval bio-max biological media.
29 people found this helpful
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Dodge charger shi fu
5.0 out of 5 starsVerified Purchase
55g submersible filter in live planted
Reviewed in the United States on December 6, 2020
I purchased this item becausr I''ve been struggling with my cascade canister filter. My first impression is that it is very strong but also dead silent. It is unlike anything else I''ve ever had. A test was ran using my new submersible filter alone and... See more
I purchased this item becausr I''ve been struggling with my cascade canister filter.

My first impression is that it is very strong but also dead silent. It is unlike anything else I''ve ever had.

A test was ran using my new submersible filter alone and then later with my cascade canister.

The cascade actually makes my water quality worse even if it had established or new media in it.

Ive added a bunch of various filters to the cascade over the years but no matter what I did, it still seemed to have alot of hazy cloudy green water - no chemicals helped either.

Eventually, ill just buy another submersible filter and stay away from the canister filters.

Update: I''ve thrown my canister filter away and only use the submersible filter, it''s much better.
2 people found this helpful
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Diane Perera
5.0 out of 5 starsVerified Purchase
Great filter for the price!!
Reviewed in the United States on June 27, 2019
This cleared up my turtle’s 40 gallon tank immediately. I had a Fluval 406 that started leaking so I bought this as a replacement. So far so good. In the past I had a Fluval submersible filter that lasted over 10 years. I am hoping to have similar luck. (Unlike the bad luck... See more
This cleared up my turtle’s 40 gallon tank immediately. I had a Fluval 406 that started leaking so I bought this as a replacement. So far so good. In the past I had a Fluval submersible filter that lasted over 10 years. I am hoping to have similar luck. (Unlike the bad luck I had with the Fluval external 406 canister filters). I think for smaller tanks this is the way to go. Just plug and play!!!!
6 people found this helpful
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melissa richardson
1.0 out of 5 starsVerified Purchase
Strong, silent, fantastic!!
Reviewed in the United States on March 4, 2020
The filter was just setup this week and already has been fantastic! The 40 gallon tank cleared up within 15 minutes of install. The best part? Silence. Absolute silence. My turtles knock on it and climb it and it stays put. I will try to update in a few months after using... See more
The filter was just setup this week and already has been fantastic! The 40 gallon tank cleared up within 15 minutes of install. The best part? Silence. Absolute silence. My turtles knock on it and climb it and it stays put. I will try to update in a few months after using it for awhile but so far, amazing.

UPDATE: Broke after 3 months, almost to the day.
4 people found this helpful
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Aerith Gainsborough
1.0 out of 5 starsVerified Purchase
KILLS FISH. They will become stuck behind the mount!
Reviewed in the United States on August 23, 2019
Was working wonderfully, I actually loved this filter until I realized fish were starting to get stuck behind it. Luckily I spotted one of my fish behind the mount, and was able to save him. But here it is today, and my beautiful koi betta found his way behind it, and I was... See more
Was working wonderfully, I actually loved this filter until I realized fish were starting to get stuck behind it. Luckily I spotted one of my fish behind the mount, and was able to save him. But here it is today, and my beautiful koi betta found his way behind it, and I was not so lucky to see and save him. He is now gone because of this filters safety failure with gaps behind the filter mount and filter itself. I would not buy this until they come up with a safer means of mounting this unit without leaving gaps. I can''t imagine how much my baby suffered trying to get out and get air. This is just horrible...
3 people found this helpful
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Top reviews from other countries

Paul J Davies
5.0 out of 5 starsVerified Purchase
So Much better than my old filter.
Reviewed in the United Kingdom on April 15, 2020
The difference this filter made to my tank is night and day, my old Aquael Turbo filter did an ok Job I guess, until it came time to clean it, having the sponge exposed and sitting below the pump was unsightly for me, but when taking out to clean it all the captured crap...See more
The difference this filter made to my tank is night and day, my old Aquael Turbo filter did an ok Job I guess, until it came time to clean it, having the sponge exposed and sitting below the pump was unsightly for me, but when taking out to clean it all the captured crap just dropped right back into the tank, was never happy with it, Now lets talk about the Fluval U4 !! …. well its like trading in a mini for a Mercedes … the 3 separate filters are easily pulled from the housing without having to dismantle the pump or remove it from the tank, ingenious design. Very powerful for my 200 Litre tank and I can easily change the filtration method by the simple twist of the control, again ingenious. One point I did notice however, and this is minor and easily sorted, after cleaning the filter pads and replacing I noticed the filter was noisier, it sounded like air was trapped within the filter housing and causing a gurgling sound, to fix all I did was lift the 3 filter compartments and drop them back down, this cleared the noise instantly, and its worth noting that the Fluval U4 runs full blast with silence. My tank water is now crystal clear with a monthly rinse out ( with tank water ) of the sponges and pads. Fully recommended. !!!
9 people found this helpful
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Glenn Perry
5.0 out of 5 starsVerified Purchase
Fantastic filter for my 80l tank
Reviewed in the United Kingdom on March 7, 2018
I bought this for my 80l tank as my U3 started to fail. I hoped it wouldn''t be too powerful for my tank and it isn''t. It works great and left the water crystal clear within a few hours (I''d cleaned the tank just before I installed it). I followed the instructions to the...See more
I bought this for my 80l tank as my U3 started to fail. I hoped it wouldn''t be too powerful for my tank and it isn''t. It works great and left the water crystal clear within a few hours (I''d cleaned the tank just before I installed it). I followed the instructions to the latter and all worked perfectly and lovely and quiet. Mine is just below water level and makes the plants (fake) sway which is nice. Just enough agitation for my clown loaches to enjoy. I''ve not tried the middle or lower outlets so can''t comment on them. I just transferred the bio stuff from my old U3 into this one and all is good. I''m hoping I won''t have to clean the filter as much as the U3. All in all, physically it''s probably just a bit big for my tank but power wise it''s perfect. I had to do some research as I noticed the blue baskets that hold the filters half of the holes were covered up which I thought was odd but apparently it''s a new design to trap more debris. For the price this filter is fantastic and should need less cleaning (for my 80l tank), although I also use a water conditioner.
11 people found this helpful
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Jacob L.
5.0 out of 5 starsVerified Purchase
I wouldnt use anything else
Reviewed in the United Kingdom on May 20, 2018
I have one of these in a 180l tank and another in a 260l tank and it works great in both. I like I can change the flow from the top to the bottom. The removable cartridges are a big improvement and makes it easier to clean. I have never found another internal filter this...See more
I have one of these in a 180l tank and another in a 260l tank and it works great in both. I like I can change the flow from the top to the bottom. The removable cartridges are a big improvement and makes it easier to clean. I have never found another internal filter this good and I prefer it over budget external ones.
10 people found this helpful
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Voice of Reason
5.0 out of 5 starsVerified Purchase
Superb
Reviewed in the United Kingdom on October 11, 2013
This is a replacement for an Eheim Powerflow 240 which I have got to say was a huge dissapointment so was sent back through the Amazon 30 day return policy. This filter is far superior to the previous product in several ways. Firstly the media changing is a lot easier and...See more
This is a replacement for an Eheim Powerflow 240 which I have got to say was a huge dissapointment so was sent back through the Amazon 30 day return policy. This filter is far superior to the previous product in several ways. Firstly the media changing is a lot easier and can be done with the unit in situ. The mechanical filtration area is a lot bigger with the biological compartment a bit smaller which makes more sense. A very nice feature is the choice of outflow from either the top/bottom jet or middle built in trickle bar. The outflow is also a lot more powerful which is reassuring. The only negative is the bio media supplied is very meagre so you may want to buy extra to fill the basket! It seems reasonably well made and carries a 3 year warranty in the UK so gives added peace of mind. Highly recommended. L
28 people found this helpful
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Andy
3.0 out of 5 starsVerified Purchase
Works OK but expected better
Reviewed in the United Kingdom on May 23, 2019
Bought to replace a JBL CristalProfi on the strentgh of other reviews on here. It''s being used on a Fluval Roma 125l tank, which in theory this U4 filter should be more than enough to handle. Whilst installing and cleaning is straight forward and inexpensive (replacement...See more
Bought to replace a JBL CristalProfi on the strentgh of other reviews on here. It''s being used on a Fluval Roma 125l tank, which in theory this U4 filter should be more than enough to handle. Whilst installing and cleaning is straight forward and inexpensive (replacement filters are cheap and easy to come by), I''ve been disappointed with the water clarity of the tank, despite regular water changes. Using on the middle or bottom filter settings the tank clouded up relatively quickly, so I''ve always had to use on the top and most powerful setting. More recently the filter completely stopped and needed a jolt to get it running again. Whilst it does an OK job my previous JBL filter produced clearer water and for longer, but was more time consuming to replace the filters and media. Will look into upgrading to an external filter next time.
2 people found this helpful
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