I went through in my head, every problem possible with having a sump and decided a float switch to turn off return pump was a must in the event the overflow fails
This will work - Amazon.com: Ultralife Float Switch: Kitchen & Dining
Or you can use an A/C condensate switch(24v) that operates a relay.
1 - Condensate switch
1 - 24v transformer
1 - Relay w/24v coil(I prefer normally open, but can be closed depending on how you wire switch)
?ft -Thermostat wire
1 - Electrical enclosure box
You can also add a time delay, so the pump doesn't get kicked off/on/off/on too quickly.
The only thing I'm concerned with is the foam that is used on the switch...And I know the arm of the switch is metal. I've heard the krylon fusion paint is non toxic, so I will try to coat it with the paint and see how it cures.
I'll post pics when I put it together...