YSI Pro20 - Manual (Page 25)

Allow the dissolved oxygen and temperature readings to stabilize. This may take 5
to 15 minutes, depending on the age of the instrument, type of sensor, and
condition of the sensor.
Press the Calibrate key. Highlight mg/L and press enter.
Use the up and down arrow keys to adjust the mg/L reading to the value of the
titrated sample. Press enter to confirm the value and calibrate or press the Cal key
to cancel the calibration.
Calibration Successful will display for a few seconds to indicate a successful
calibration and then the instrument will return to the run screen.
If the calibration is unsuccessful, an error message will display on the screen. Press
the Cal key to exit the calibration error message and return to the run screen. See
the Troubleshooting guide for possible solutions.
SALINITY COMPENSATION CALIBRATION
The Pro20 uses a user inputted salinity value in ppt (parts per thousands) to
compensate dissolved oxygen mg/L values. The salinity compensation value
entered in the Pro20 should be the salinity value of the water you are testing.
To adjust the salinity compensation value, use the up or down arrow keys to
highlight the salinity box on the run screen, and then press enter (Figure 10).
Next, use the up or down arrow keys to adjust the salinity compensation value to
the salinity of the water you are testing. You may enter a value between 0.0 and
70.0 parts per thousand (ppt). Press enter to confirm and to save the new salinity
compensation value.
The salinity compensation value can be adjusted any time without the need to
recalibrate dissolved oxygen.
6.58
mg/L
95.9
%
24.2
°C
21
SAVE

DATA
729.7
mmHg
35.0
ppt
Figure 10, Salinity box highlighted.