This is a master file copied from https://gist.github.com/layerzerolabs and modified by me. The whole post is focused on swimming pools and Node Red integration. It is based on the MQTT protocol and expects values ​​from it. No matter what sensors you use, everything should be in mV. You can check here: https://www.hannainst.com/hubfs/006-finished-content/pH_Guides/calculating-a-ph-slope-percentage--hanna-instruments.pdf Enjoy.