[PlantedRich]

I would call this needing a controller. A controller often has a probe that goes into the tank and then the heater is plugged into the controller. The thermostat on the heater normally controls the temperature of the tank but if it fails the controller will cut the power and save the fish. One can buy off the auction and I do that when I need large numbers but they can also require some DIY work. When I want a really slick looking, good unit with lots of really nice features, I go with the Inkbird for all around quality at a price that I find okay.