Why WiFi the hot tub ? Last month (Oct 2017) I decided to try to connect my hot tub to the web as an IoT device. Initially I wanted to be able to turn the heater on and off on a schedule, but once on WiFi, I would be able to control the temperature remotely. At first I employed a hot tub service to put in the necessary chemicals each week. I found this write-up at poolspaforum and found I could do a better job of regulating the hot tub chemicals if I did it myself. There are a number of advantages of having the hot tub connected to the web. These are: To control the main pump filtering times To control the temperature during different times of day or when away on vacation To get any error messages from the hot tub To eventually automate the water sanitization chemical addition 1. Main parts of the hot tub The hot tub has three main electrical parts: An internal controller circuit board, with connections to sensors A set of buttons to control the hot tub