YSI 6000UPG - Manual (Page 40)

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Place 500 mL of the chilled 1 mg/L standard solution in a clean calibration cup. Carefully immerse
the probe end of the sonde into the solution.
Allow at least 5 minutes for temperature equilibration before proceeding. Press Enter and input the
concentration value of the standard as requested or accept the default. Press Enter and the current
values of all enabled sensors will appear on the screen and will change with time as they stabilize in
the solution. Observe the readings under NH4+ or NO3- and when they show no significant change
for approximately 30 seconds, press Enter.
After the third value calibration is complete, Hit any key to return to the Calibrate menu.
Thoroughly rinse and dry the calibration cups for future use.
CALIBRATION TIP: AVOIDING DRIFT DURING CALIBRATION OF THE NH4+ AND
NO3- PROBES AFTER pH CALIBRATION. Exposure to the high ionic content of pH buffers
can cause a significant, but temporary, drift in either the ammonium or the nitrate probe.
Therefore, when calibrating the nitrate or ammonium sensor, we recommend that you use one of
the following methods to minimize errors in the subsequent readings:
❏ Calibrate pH first, immersing all of the probes in the pH buffers. After calibrating pH, place
the probes in 100 mg/L nitrate or ammonium standard and monitor the reading. Usually, the
reading starts low and may take as long as 30 minutes to reach a stable value. When it does,
proceed with the calibration.
❏ When calibrating pH, remove the probe guard and immerse only the pH and temperature
probes in the buffers. You can then calibrate nitrate or ammonium immediately after pH
calibration.
TURBIDITY 2-POINT
Select 9. Turbidity from the Calibrate Menu and then 2. 2-Point.
NOTE: One standard must be 0 NTU, and this standard must be calibrated first.
To begin the calibration immerse the sonde in approximately 300 mL of 0 NTU standard (clear
deionized, distilled, or tap water), as instructed, and press Enter. Input the value 0.00 NTU at the
prompt, and press Enter. After calibration of the mechanical wiper speed, the screen will display
real-time readings which will allow you to determine when the turbidity values have stabilized. If
the readings appear unusually high or low or are unstable, there are probably bubbles on the optical
surface. Activate the mechanical wiper by pressing the “3” key to remove the bubbles. After
stable readings are observed for approximately 40 seconds, press Enter to “confirm” the first
calibration and then, as instructed, Hit any key to continue.
WARNING: THE TURBIDITY SENSOR CAN ONLY BE USED AT DEPTHS OF LESS THAN
200 FEET (61 METERS). USE OF THE PROBE AT GREATER DEPTHS IS LIKELY TO
PERMANENTLY DAMAGE THE SENSOR.