I found this sensor, but no electronic link. I'm sure it's useless for our purpose, but it gives an idea of what I'm looking for:
http://www.sciencekit.com/Products/D...egoryID=193995
versus what I'm NOT looking for:
http://www.controleng.com/archives/p...ruary/p401.htm
As for the level sensor, this is the cheapest I could find:
http://www.omega.com/toc_asp/subsect...K12&book=Green
(It's basically a float mounted magnet, with a reed switch)
I did find thermal sensors:
http://www.omega.com/ppt/pptsc.asp?ref=5TC&Nav=tema02
Maybe someone can give us an opinion on those, or a better source! I'd also need to rig them up for in-line operation...