Predrilled reef tank inlet location question

[runway1]

I'm having a 120 gal predrilled for bulkheads for a closed loop system. Currently, I'm planning three returns near the top of the water level (typical).

Has anybody tried maybe a return near the bottom of the tank behind the rocks to remove any dead spots? Any links or suggestions on a closed loop, predrilled, layout. TIA!

 

[fishfreek]

With a closed loop indeed you can put a return at the bottom. INfact that might be more desirable and have the closed loop intake toward the top.