My spa temp range is running ~102.5 to 107.5 with the the last two thermostats I have put in it. Unless my memory has completely failed me, the previous one ran 103 to 105. What should I expect? The spa is a cal fun-x.

I can expand on my own question now. A vendor has told me that the normal
range for mechanicals is +-3 degrees so mine is good. Not good enough, but good. So now I delve into the redesign. I am a industrial electronic tech and pretty electrician as well. The gloves are coming off. Has anyone else done an upgrade on the mechanical controls to get better control on the Spa. I'm thinking all electronic with at least x10 monitoring if not actual control.