waverider
Member
I just picked up a 2 point ph pen today. I ran into a problem trying to calibrate it. I can calibrate point 1 to read 7.0 But when i try to calibrate point 2 to read 4.0 it will only goto 3.5 I am using calibrating 7.0 and 4.0 solution. Does anyone know how to calibrate point 2 to make it say 4.0?