I only tried FBFs once before. I gave up ot it before I got to really use it. Onlky reason whay was because I had a barebottom tank and I had the FBF return to the tank. Littls bits of sand would get through and it would the hell out of me so I took it off right away. But I can see the idea working, I just need to find the funds to buy 4 of them plus pumps.