CLI returning null is ok and as expected . It means it’s workingI'm using putty to get to the CLI in the reef-pi (x.x.3.187) itself, so the commands im inputting are going directly to the reef-pi. The json files are located on the desktop of my PC (x.x.3.229), as well as the download folder in the reef-pi. Any commands from the reef-pi to the reef-pi result in the CLI returning with null. Any commands to the PC result in a connection failure due to timeout over port 80. I'm missing something here, and I can't figure it out. Should I be executing these commands from the desktop of the reef-pi? I did do a full OS load on it, so it does have a desktop. Should the json files be placed somewhere specific in the reef-pi or my PC? If anyone besides @Ranjib knows how to do this, please let me know. @theatrus, how did you go about calibrating your probes for testing? What am I missing?