Fluval U4 Poly/Clearmax Filter Cartridge

By Fluval
Rated 2.8333 out of 5 stars
$18.99Chewy Price
$18.04Autoship Price
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FREE 1-3 day delivery on first-time orders over $35

About This Item


  • Helps control green water and unsightly algae growth for a clear, beautiful tank.
  • Chemical filter media helps to absorb and trap phosphate, nitrite and nitrate.
  • Encourages crystal clear water, helps to reduce odors and encourages the ideal conditions for fish and plants.
  • Helps to reduce overall aquarium maintenance, so you can enjoy your tank more and worry about it less.
  • Convenient two-pack gives you one cartridge for now, and one for later.

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Compatible Products

Ensure your system runs smoothly with Fluval Underwater Filter.

Frequently Bought Together

This Item – Fluval U4 Poly/Clearmax Filter Cartridge
Rated 2.8333 out of 5 stars
$18.99Chewy Price
Fluval U4 Foam Pad Filter Media
Rated 4.5 out of 5 stars
$5.79Chewy Price
Fluval U3 Poly/Carbon Underwater Filter Media, 2 count
Rated 4.6667 out of 5 stars
$9.49Chewy Price
Total Price: $34.27

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Fish TypeMarine Fish, Tropical FreshwaterMarine Fish, Tropical FreshwaterBetta, Goldfish, Marine Fish...Marine Fish, Tropical FreshwaterMarine Fish, Tropical Freshwater
Aquarium TypeSaltwater, FreshwaterSaltwater, FreshwaterSaltwater, FreshwaterSaltwater, FreshwaterSaltwater, Freshwater
MaterialSynthetic Fabric, PolyesterSynthetic Fabric, MeshFoamPlastic

Questions & Answers

1 Customer Questions

What are the dimensions of these filters?
Answer by ChewyNov 06, 2018
The dimensions are 8.6 inches long x 2.4 inches wide x .7 inches high.

ReviewsWrite a Review

Rated 2.8333 out of 5 stars
6 Ratings
Would recommend to a friend

6 Customer Reviews

Rated 1 out of 5 stars
By Disappointed on Sep 20, 2020

weird red brownish stuff on new items

Why did my cartridge arrive with this red tint to it???? So confused

Rated 5 out of 5 stars
By Bridgett on Aug 24, 2018

Love these filters

I have always paid more and got the filter for algae but reading the reviews I decided to get the plain filters to save money, big mistake, within a couple of days our tank was a mess with algae and discoloration and odor I never had that problem with these filters I recommend them 100%, I have a very large red earred slider and it is hard to keep his tank clear, but not with these filters I will never buy the plain filters again these get the job done!

Rated 1 out of 5 stars
By tortuga on Jul 3, 2017

these do not work

The carbon filter cartridges work. These do not. I can do a 60% water replacement and the water is murky and filled with fine particulates the day after installing these with new sponges. The carbon filters work. These do not.

Rated 4 out of 5 stars
By Mimi on Nov 21, 2016

Fluval filter

This product does it's job well and my tank benefits from it.

Rated 5 out of 5 stars
By xxLauraxx on Sep 19, 2016

good product

Good product and I like ordering from chewy. Good prices and fast delivery.

Rated 1 out of 5 stars
By Bethany on Aug 25, 2016


To be fair I thought I was ordering the carbon filters, but didn't pay close enough attention. However, I gave these a try and found them to be next to useless. The water is consistently cloudy. The description says they will collect fine particulates, but this is simply not true. I absolutely love my filter and other filter pads that are available, but will never order these again. Blessedly this was an inexpensive mistake.