I would like to monitor the temp in our hot tub and get an alert if the water temp goes below a certain temp. This time of year if the heater were to stop working you can have a real mess on your hands with frozen/damaged pipes & pumps.
I’m looking at the first gen of the Fibaro FGK-101 which allows for external probe attachment. I was looking to pair it with the DROK DS18B20 prob and just hang it over the side of the hot tub into the water.
I started thinking about a way to make this install cleaner…The hot tub has a built in probe that attaches to it’s motherboard so it can monitor it’s temp. Would it be OK to tie into this same probe?
No, in general those probes work on some type of resistance. Adding wires to monitor the existing probe will more then likely cause that resistance to change and it will no longer be accurate. You’ll want to add your own probe like you initially planned.
I’m not sure of any sensors that would let you use that 3/8 well either. Also not sure if you want to go down the DIY route but if so you could use the ST_Anything project with a Adafruit DS18B20 waterproof sensor & a ESP8266 chip to send the temp to SmartThings.