YSI 600DW-B Sonde - Manual (Page 81)

Sondes Section 2
Select the 2-point option to calibrate the chlorophyll probe using only two calibration standards. In this
case, one of the standards must be clear water (0 µg/L) and the other should be in the range of a known
chlorophyll content of the water to be monitored. For example, if the water to be evaluated is known to be
low in chlorophyll, an appropriate choice of standards might be 0 and 10 µg/L. However, for general-
purpose measurements an appropriate choice of standards is usually approximately 100 µg/L.
To begin the calibration, immerse the sonde in the 0 µg/L standard, as instructed, and press
Enter. It is
mandatory that the 0µg/L standard be calibrated first. The screen will display real-time readings that will
allow you to determine when the readings have stabilized. Pressing
Enter will confirm the first calibration.
Following the instructions on the screen, place the sonde in the second chlorophyll standard, input the
correct value in µg/L, press
Enter, and view the stabilization of the values on the screen in real-time. After
the readings have stabilized, press Enter to confirm the calibration. Then, as instructed, press any key to
return to the Calibrate menu.
Select the
3-point option for maximum accuracy over the entire range of 0 to 400 µg/L. As with the 2-
point procedure, one of the standards must be 0 µg/L. The user can select any values for the second and
third standards that are deemed appropriate. The procedure for this calibration is the same as for a 2-point
calibration, but the software will prompt you to place the sonde in the additional solution to complete the 3-
point procedure.
For all chlorophyll calibration procedures, be certain that the standard and sensor are thermally equilibrated
prior to proceeding with the calibration
CAUTION: To be assured of the accuracy for field measurements made with your chlorophyll sensor, you
must either initially calibrate the sensor using a phytoplankton suspension of known chlorophyll content or
post calibrate you sensor in a spreadsheet by comparing the fluorescence values obtained in field studies
with those obtained by laboratory analysis for chlorophyll on grab samples collected during the field study.
The use of chemical dye standards for “calibration” of the sensor may not result in accurate correlation
between fluorescence and actual chlorophyll readings and is designed primarily to evaluate the sensor for
drift. See
Section 5. Principles of Operation for more information on the proper calibration of your
chlorophyll sensor.
OPTIC RHODAMINE WT
When selecting Rhodamine, there will be a choice of 1-point, 2-point, or 3-point calibrations for your
rhodamine WT sensor.
The
1-point option is normally used to zero the rhodamine probe in 0 ug/L standard. Place the sonde in
clear water with no suspended solids, and input 0 ug/L at the screen prompt. Press Enter and the screen
will display real-time readings that will allow you to determine when the rhodamine readings have
stabilized. Press
Enter after the readings have stabilized to confirm the calibration and zero the sensor.
Then, as instructed, press any key to return to the Calibrate menu.
Select the
2-point option to calibrate the rhodamine probe using only two calibration standards. In this
case, one of the standards must be clear water (0 ug/L) and the other should be in the range of the predicted
rhodamine concentration projected for the study. For general purpose measurements an appropriate choice
of standards is usually 0 and 100 ug/L.
To begin the calibration, immerse the sonde in the 0 ug/L standard, as instructed, and press
Enter. It is
mandatory that the 0ug/L standard be calibrated first. The screen will display real-time readings that will
allow you to determine when the readings have stabilized. Pressing
Enter will confirm the first calibration.
Following the instructions on the screen, place the sonde in the second rhodamine standard, input the
correct rhodamine value in ug/L, press
Enter, and view the stabilization of the values on the screen in real-
YSI Incorporated Drinking Water Monitoring Systems Operations Manual 2-74