Piggyback switch for a utility pump

[Lonny]

Anyone know where to get a switch for a utility pump? It is for the inside of my solution tank in a porty. It has to be able to withstand high heat. I had a float switch from Home depot, but the bugger didn't have thermo resistant plastic, it was warped all to crap after the first use.
The switch needs to either be a pressure switch that is activated at 0 psi and turns off at approx 50psi, or a thermally resistant float switch is great too.