How did this project go? Did you end up completing it? Recently my apex el crapped out and basically shutdown my tank. I got it working again by resetting the circuit in the back, butI don’t like having everything rely on that one system especially with it being less than 6 months old, and now I’m looking for a way to alert if my ranco thermastat dies. Bought a pi zero and some ds18b20 probes. Going to solder one of them on the pi board here in a few weeks and then see if I can find an already made project or cobble something together that can alert me if temps get out of whack.