Arduino water level control for aquaponics and ring it to a beeperThis is a good reason to get those inexpensive digital thermometers with high/low alarms.
.............now, if they would just make an inexpensive and simple device that warns you when you're about to flood the tank
I use buckets so I'm safe, and I just feel if the water is similar temp, no obvious effects from this method so i think I'm okay