honestly, I did it because it's how the tank builder recommend too, he has his clown fish breeding tanks set up like this and after looking at his system up and running i dicided I liked it enough to copy it. It makes for easy flow adjustment and with the stand pipes I can have the rack pushed right up against the wall saving space. All the return water is at the front of the rack and is easy to play with. the return pump it's self (aqua medic dc runner 5.0) has an electronic hand controller to adjust the flow and even has a "feeding" function that stops the return water for a while then auto starts up again.