or is it that you want the temperature level monitored all the time
Yes I want the temp monitored all the time, My digital thermometers have a high/low temp alarm and the alarm has saved me a few times. I once had a faulty heater that didnt turn off and when the water temp got to 33 deg C the alarm sounded and this was at 2 am.
Another time a circuit breaker tripped and the alarm sounded when the water got down to 20 deg C again this was during the night.