The Inkbird ITC-306A is one of the most reliable Aquarium temperature controllers there are. Connected through wifi with in app functions you can monitor and control your aquarium temperature. Must use when safety is a concern, which it should be.

Inkbird Aquarium Temperature Controller
One of the most important safety measures in your tank is a good Temperature controller. I rely on this Inkbird ITC-306A
Inkbird Aquarium Temperature Controller