YSI ProDSS - Manual (Page 40)

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Calibration
Figure 48 Calibrate ODO mg/L
ODO mg/L calibration
1. Place the ODO and conductivity/temperature sensor into a water
sample that has been titrated by the Winkler method to determine
the dissolved oxygen concentration in mg/L.
2. Push the Cal key, then select ODO. Select DO mg/L.
3. Select Calibration value.
4. Enter the dissolved oxygen concentration of the sample in mg/L.
5. Observe the actual measurement readings for stability (white line
on graph shows no significant change for 40 seconds), then select
Accept Calibration ( Figure 48 ). “Calibration successful!” will be
displayed in the message area.
6. Rinse the bulkhead and sensors in clean water then dry.
Figure 49 Calibrate ODO zero point
ODO zero point calibration
1. Place the ODO and Conductivity/Temperature sensors in a
solution of zero DO.
NOTE: A zero DO solution can be made by dissolving
approximately 8-10 grams of sodium sulfite into 500 mL
of tap water. Mix the solution thoroughly. It may take the
solution 60 minutes to be oxygen-free.
2. Push the Cal key, then select ODO. Select Zero.
3. Observe the actual measurement readings for stability (white line
on graph shows no significant change for 40 seconds), then select
Accept Calibration ( Figure 49 ). “Calibration successful!” will be
displayed in the message area.
4. Thoroughly rinse the bulkhead and sensors in clean water then
dry.
5. Perform a ODO % water-saturated air calibration after performing
a zero point calibration.