looking for controller

[e46er]

so would I set a heater at like full on 90* and the controller gets set at say 77* heater plug on and and 80* heater plug off?

becuase the thermometers in the heaters are crappy if the controller gives the plug power at 77* and the stupid cheep heater says its fine it wont come on and tank keeps getting cooler...................... it would make sense to keep the ehater at a high enough temperature to make sure it would always turn on when the controller plug outlet gets power