sump help needed

[dunl]

Okay, I bought this setup off of one of our members in Calgary, but didn't get a chance to ask too many questions as to how things were set up:



An 802, 602, and 2X402 Powerheads with critter guards came with it.

The tank has an overflow in the centre of the back. There is two bulkheads....three actually. One is in the bottom of the overflow of the sump. The other has one bulkhead almost at the top of the overflow box into the tank, where an l shaped pipe runs to the bottom of the overflow box to the sump.

I need to know how to set this up perfectly so that it is a silent system. No flushing, no gurgling, no splashing....just the hum of the pump.