I have the 4" model. I gotta say, it's my first and only piece of equipment that I would not recommend to a friend. It just doesn't work as well as it should. My sump has become dirtier since switching from socks to this roller filter. I feel awful giving it a bad review, but I've tried so hard to tinker with it, thinking it was something I was doing wrong. It just isn't a great product, unfortunately.