YSI ADV6600 - Manual (Page 67)

Section 4. Calibration and Diagnostics
ADV6600
Y S I
Environmental
Page 57
equilibration before proceeding. (Allow at least five minutes for the third, chilled standard
in a 3-point calibration.)
3. From the Calibrate menu, select ISE NO
3
- to access the nitrate calibration choices and
select either a 1-point, 2-point, or 3-point calibration.
4. Input the value of the first standard at the prompt.
5. Press Enter and the current values of all enabled sensors will appear on the screen and
change with time as they stabilize in the solution. Observe the readings under NO
3
-
and
when they show no significant change for approximately 30 seconds, press Enter. The
display will indicate if the calibration is accepted.
6. Press Enter again, as instructed on the screen. If a 2- or 3-point calibration was chosen,
rinse the sonde in water and dry the sonde before proceeding with the next nitrate standard,
following the same steps as outlined above.
Nitrate sensors generally drift more than pH sensors. To check for this drift, place the probe in one
of your standards at the end of each deployment.
Nitrate standards are good growth media for a variety of organisms. This growth can significantly
reduce the nitrogen content of your standards, an effect that is particularly important for the 1 mg/L
solution. It is best to use new standards for each deployment, but if you decide to save your
solutions for reuse, we recommend refrigerated storage to minimize the growth of these organisms.
The nitrate sensor should not be exposed to pH calibration buffers. If accidentally exposed, the
nitrate readings will be erratic and take longer to stabilize. To restore function of the nitrate sensor,
soak the probe in 100 mg/L standard for a few minutes to several hours (or overnight). Perform a
new calibration and pay careful attention that nitrate readings are stable.
CAUTION: The nitrate membrane module is for use only at depths less than 50 feet (15.2 meters).
Use of the probe at greater depths is likely to permanently damage the sensor.
4-6.9. Chloride
When selecting to calibrate Chloride, you will be given the choice of a 1-point, 2-point, or 3-point
calibration. The temperature response of ion selective electrodes is not as predictable as that of pH
sensors. Therefore, be sure to carry out a 3-point calibration the first time you use the probe. This
will provide a default setting for the effect of temperature on your particular sensor. After this
initial calibration, you can use the less time-consuming 2-point and 1-point routines to update the 3-
point calibration. However, it is strongly recommended to perform a new 3-point calibration after
each deployment of 30 days or longer.
A 1-point calibration is used to adjust a previous calibration, using any solution of known chloride
concentration.