How to display temperatures in a hot water tank

[Holdestmade]

Have a look here, someone has done similar to what you want to do

Six Temperature Sensors on a Hot Tank

My home heating system includes a 80L hot water tank, which is heated by a gas boiler. During the summer (i.e. now) it’s set to heat for an hour in the morning and an hour in the evening. I’ve put 6 equally spaced temperature sensors up the side of the tank, connected to a Sonoff Switch, flashed with TASMOTA. For your delectation, here is a graph of those sensors over the last 8 hours. Heating came on at 17:00 and folks took their showers at 17:30, 17:40, 21:40 and 22:00. I have a great data…