- Apr 12, 2008
- Reaction score
I have a REF103 refractometer that does not seem to want to zero out. I calibrated it using some distilled water. When I adjust the calibration screw the line is at the bottom of the zero and not at the actual zero line If I screw in the screw the light dark field gets lower. If I turn the screw out it does not go above the bottom of the "0". The instructions say to adjust the screw to make the light dark boundary coincide with the null line. What exactly is the "null line"?