I have this Sharp ph40 ph testing pen (attatched pic). I haven't used it in years. What the hell are the buttons "cal" and "CFM" for? I'm pretty sure there for calibrating the pen but I don't know in what combination or how exactly they work. Can anyone help with this?
Stormcooker Reviewed by Stormcooker on . ph tester pen help!!!! I have this Sharp ph40 ph testing pen (attatched pic). I haven't used it in years. What the hell are the buttons "cal" and "CFM" for? I'm pretty sure there for calibrating the pen but I don't know in what combination or how exactly they work. Can anyone help with this? Rating: 5