Here's a pic of my setup. Haven't done the spring cleaning, so pardon the mess.
The aluminum box houses a standard bilge pump float switch. I made the box out of some aluminum sheet I picked up at the local Ace Hardware. In addition to supporting the switch, it keeps bait fish from interfering with float switch function and keeps sloshing water from short cycling the switch. Just by dumb luck, the mounting height is just right. The switch kicks in when the water level is about two inches below the top, and pumps it down about an inch before shutting off. The wires from the switch pass through a 1/8" hole into the bilge. The hole for the wires and the screws supporting the box are sealed with 5200.
The pump outlet is on the lower left with an off the shelf bait well strainer. The doohickie plugged into the drain, also off the shelf, allows water to flow in while at anchor, but keeps it from draining dry while on plane.
The inlet on the right is connected to a seacock that forces water into the livewell while on plane. I have a ball valve on that line accessible through the starboard transom hatch that I use to throttle water flow to the live well.
I have been very happy with this setup. I mainly use it for pin fish and they do very well.
