I have a G6 on my 33L CRS/CBS tank. Because I have shrimplets, I use an ATI sponge from an ATI sponge filter setup as the pre-filter that goes over my intake. It fits perfectly, and doesn't restrict my flow in any noticeable way. I have quite a bit of moss and as well as some stem plants and floaters in the tank, but I still find myself rarely having to rinse the cartridges. I usually do it every couple of months because I should, but I never lose any flow according to the meter. I suspect that large pre-filter is helping a lot. I really couldn't be happier with this setup on the shrimp tank. The only modifications that I did do was make my own spray bar that runs 36" along the tank. That was just for flow reasons in a shrimp tank, though, nothing really related to the filter performance.