Hello, how can I calibrated pH meter without the supplied buffer? I use a POIT pH meter. Thank you.
I have never use this type, but as far as I know, there is no DIY of calibration for any pH meters. Hight recommend you obtain the correct solution or powered to calibrate it. Most hydroponics stores carry some form of calibration solution (4.0, 7.0). I’m not sure if your meter uses those numbers.