You can buy off ebay a mini digital temperature controller then go to your local hardware store and buy a double gang box, a receptacle, and an extension cord, and a face plate for square receptacles. With all these things you build a temperature controller. There is a form of how to by looking up “aquarium temperature controller” . You can build this for about $30. I am a Radar Technician so this was childs play for me and hopefully for you . If you can’t build one yourself I can build it for you and get $20 over materials and shipping. These do normally read only Celsius.