Glad to know it did the job! The first year I used my greenhouse, I actually slept out there for a night before I put the plants out so I could check the drops in temperature in person! I still get razzed about it each spring when I first put the seedlings out - am I going to bring my sleeping bag out? I have two remote thermometers in each end of the greenhouse and on super cold nights get up every few hours to check, just in case the heater quits on me or power goes out for some reason. Sure would be comforting to have an alarm like yours.
