Click the link in my signature, then scroll down to the pic where you can see the gas tank and click on it. The pic is too large to post here, but you can see what I did.
This is a view from the transom. The ice chest on the left is for ice, I just let it drain into the bottom of the boat when I'm done for the day, and the water runs out the boat drain. The live well is on the right. There are three penetrations into the live well. One at the bottom with the valve attached that you can see. The clear tubing at the top goes to the spray nozzle, and the black flex tubing is an overflow drain that penetrates the boat hull on the right. With both valves open, the live well drains. With only the transom valve open, the pump brings in fresh water and the water leaves through the overflow. With only the live well valve open, the pump recirculates the water already in the live well, and allows aeration when I'm not in the water. This setup allows me to have both functions served with only one pump.