Heating question

[twiddledog]

I have a 72 gallon AGA bowfront with an overflow and a sump\refugium. I am curious where the best places are to put my heater element and the sensor. I was thinking of putting my heater element in my overflow and my sensor in the tank but I am not sure if that is the best way.
Any suggestions?

 

[Andy O]

I have mine set up with my temp probe in the overflow and the heating element in the sump. I also run a back up heater in the main tank as well just in case.