Vertex Refractometer

[PuffLuv]

I just bought one this week. I used distilled water to calibrate it, leaving it on the lens for about a minute to adjust to the correct temperature. It was out of calibration by a couple points when I received it, so I turned the screw slightly with the supplied screwdriver and it is now accurate. J&L had another refractometer for almost $10 more, but the only thing really different is that it came with its own "pure" water. Supposedly, "they look like they come from the same plant".