Negative ppm reading???

Hello I've looked for a minute so I'm sorry if this is in a different post but what is it when my ppm meter starts reading negative numbers

Probably something wrong with the PPM meter. Have you tried to recaliber it?

New batteries often fix them up. Never seen negative numbers tho.

From what I understand it means the liquid is holding a charge. I was just trying to figure out what a person could have in there soil that would have a charge. The ppm meter is new btw