Putting your probe in a jug of water is fine for a kegerator, but in a fermentation setting, you should be monitoring the temperature of the beer. Fermentation puts off heat, so the beer is likely several degrees warmer than that water. At least, in my very limited experience (first lager ever is in the ferm chamber right now), that's what I've noticed.
Tap 1: Flanders Brown Tap 2: Pumpkin Ale Tap 3: Rye IPA Tap 4: Wee Heavy Tap 5: Apfelwein
Fermenting: Amber Ale
Kegged: Barrel-Aged Barleywine, Barleywine, RIS,