I do not fish much so I have never had to hook up or use a livewell with an aereator system.
A boat we are building is wanting a livewell setup with aereator.

For the most part I understand the concept You have to let water in and then need an overflow drain.

But how do you keep from overfilling?

then there are timers, how exactly do you hook these in to circulate the water? Just like you would a regular switch?

What is a good pump and timer and other parts?

On my old boat I had a timer with swich all you had to do was run a hot to it then run a wire to your pump. My pump just screwed into a hole I drilled in the back. Just run an overflow out the side of the boat and into your livewell at the height you want your waterto be.

You have an overflow like riverrat mentioned.

Also, to really keep fish & bait alive an oxygen system is a must have. The bait / fish come out of there on crack

if he is bass fishing i'd recommend a recirculate also...

I use a portable Keep Alive, it keeps shrimp alive for 2 days with same water.

This is a good website for livewell ideas and diagrams. They also make great products.

http://www.shurflo.com/marine-products/ ... fault.html

Shurflo Piranha pumps are great. That's what I would use. There are a thousand different ways to set up a livewell. I would ask your customer what he wants and go from there.