Fluval U Underwater Filter BioMax, Replacement Aquarium Filter Media, A495

Does the job been only 2 weeks and I already see some bacterial build up on the media.

I got this to fill the cartridge of my U4 filter. They seem to be working as expected and I am happy with them.

Works great

We use this in our Fluval U2 Filter for our turtle. In combination with the other filter refills, it keeps the turtle clean nice for an extended period of time.

Using with my U4 filter, which is working out great in my turtle tank

Biological filtering is the way to go. One of the best aspects of the Underwater U series is that they approach water cleanliness through a comprehensive approach, including BioMax. These little white nuggets work like magic for the water of my turtle tank.

Exactly what I needed!

Just as described, perfectly happy with the purchase! And of course my RES is loving it even more!! :-)

Ive used several different filter systems on my various aquariums. I love this underwater one the most. No constant running water. It keeps the tank clean and the filter elements last a long time.

We needed filter refills for our turtle tank. We use the U3 filter. These did the trick.