[yodaddy]

I did it using 2 bilge pump switches mounted in the live well. The switch for the inlet pump is mounted upside down a couple inches below the top of the livewell. The discharge switch is mounted rightside up a couple of inches below the inlet switch, so that about the time the inlet switch opens (turns off the inlet pump), the discharge pump runs and drops the water level and the inlet pump kicks in again.

Your discharge pump has to be of a higher capacity than your inlet pump for this to work.

I'm using a through stern pump for the inlet, with the inlet hose coming in at the top of the tank, and the discharge pump is a bilge pump mounted to the bottom of the livewell.

We've kept mackeral alive for days in this setup.