[daffyfish]

I have a U3, that I use as a second filter, in a 58.
It does a good job.
I don't use the poly/carbon cartridges. I just cut some filter media, instead.
I have a U4, that I tried using in a 75, but it created too much flow.

 

[daffyfish]

Yeah, it created more flow than my XP3!
That's why it is back in the box waiting for a bigger tank.
:red_mouth

 

[daffyfish]

Yes it does a good job.
I like the flexibility of putting different media, in the trays.
Plus not having to remove the whole filter, to change media.
What size tank are you thinking about putting it into?
Does take up some room.

 

[daffyfish]

The U4 is quiet.
But, it does take up tank space.
Some tall plants, will camouflage it.
Here's a video that I found.
May answer some questions for you.


http://www.youtube.com/watch?v=tq4RVt3omgE&feature=related