Here was the breakdown of the refractometer calibration station:
|Total refractometers tested: 22|
|Number out of calibration: 12|
|Number calibrated: 11|
|Number unfixable: 1|
|Number of broken ones: 4|
|Number <1.026 (Cal. Fluid Std.): 8|
|Number >1.026: 4|
Most common refractometer problems:
1) Most (15) refractometers had the same issue: the clear plastic cover hinge was rusted. This is probably due to not rinsing it off after use with RODI water and not drying it off. I suspect that they were placed back into their sealed plastic boxes until the next use. The plastic box retains the moisture and promotes hinge rusting.
2) Several refractometers had the top clear plastic cover completely broken off. While not the best working condition, it still allows for measurement.
3) One refractometer was completely broken: the eyepiece lens did not allow for clear or sharp reading of the interface or scales and the adjustment screw did not work..
4) One swingarm was brought in to check and it was reasonably accurate. However, it took several taps of the casing to get the swingarm to float properly. The biggest problems with swingarms is that they must be rinsed well with RODI water to get rid of the salt/mineral deposits and bubbles, and they do not correct for temperature. Three TDS Meters were brought in for checking.
|Number > calibration fluid: 2|
|Number < calibration fluid: 1|
NOTE: The TDS meters were only slightly out of calibration. In reality, the main testing range is 0 - 10. You can accept RODI within this range as the reading will increase dramatically when the filters or membrane goes bad.
I would like to thank MASM for having the Calibration Station available at the MASM Swap and Tom (CalmSeasQuest) for bringing in his TDS Meter and TDS fluids.
is the link to get a copy of instructions on the care and use of the refractometer and TDS Meter.