Sveral times people metion inkbirds on here, what models are you using? Just looking for a simple safety in case the heater gets stuck on, but many models are programmable day night, or on off times, etc. More complicated than necessary.
Any of their models will work but eventually, their probes will corrode and fail. Get the newer model (Inkbird ITC308S) that has a replaceable probe.
They seem complicated at first but all you have to do is plug the heater into the “heat” side, set your parameters like max temp, and you’re done. You can do the same on the “cool “side if you want to plug in a fan.
The only other feature I use is the alarm which goes off if the tank ever goes over the max temp but a certain number of degrees (programmable).