I have a closed loop on my 120 gallon tank. An Ampmaster 3000 is the pump being used, and it runs through a Motorized Ball Valve. The timer on this is set at ~5 minutes, so I switch from one side of the tank to the other every 5 minutes. The bottom outputs of my closed loop are designed to serve as a spray bar, instead of having an actual spray bar. It works very well at keeping detritus in suspension, to go in the overflow and into the sump. Anyway, this is my set-up (also, I don't recommend this set-up on a tank with DSB, as the concept of my tank is to remove detritus and waste, instead of process it - if this was used in conjunction with a substrate, I think there would be a perpetual sand storm).
This is the shot after drilling:
Here is the inside:
