Warning: Unlike the Temperature Compensating model, the Non-Compensating Refractometer is
used for close, approximate salinity measurements. The salinity scale is based on a 20 degree
Celsius fixed temperature. Therefore, is is only at this temperature that a true, accurate reading can
be made. Taking readings outside the 20 degree C fixed temperature will decrease measurement
accuracy. Re-calibrating the unit to zero in the new ambient temperature (other than 20 deg C) will
give a more accurate reading. For exact readings in varied temperatures, the Aquafauna Automatic
Temperature compensated model should be used.
Allow the Aquafauna refractometer to rest for approximately one hour in the ambient temperature in
which you will be taking readings (20 deg C for exact measurement). Place distilled water under the
daylight plate. The boundary refraction line should read 1.000 specific gravity or 0 ppt. If the
boundary refraction line is above of below the 1.000 specific gravity/0 ppt marking on the scale,
remove the plastic cap (new model do not have cap) and calibrate as described above under
"Calibrating the Automatic Temperature Compensating Model".