Nova-Tech DO 700 - Manual (Page 14)

4) Press . The CAL indicator will blink and the secondary display
will indicate the calibration point, 0.0.
5) Press to confirm the calibration. The primary display will blink
briefly before calibrating to 0.0%.
6) Press to return to measurement mode, or continue with 100%
calibration if desired (note 0% calibration followed by 100%
calibration is not recommended---always perform 100% calibration
first).
4.5 mg/L or ppm (Concentration) Calibration
Performing a saturation calibration at 100% or 0% will simultaneously
calibrate the corresponding mg/L (ppm) concentration value.
Therefore, additional mg/L (ppm) calibration isn’t required in most
circumstances.
If desired, you can perform a calibration adjustment in mg/L (ppm)
without affecting your % saturation calibration value.
1) Rinse the probe well with clean water (do not dry).
2) Press to select concentration mg/L (ppm).
3) Dip the probe into a sample of known oxygen concentration (i.e.
determined by titration or another instrument). Wait for the reading
to stabilize.
4) Press . The CAL indicator and current concentration display
briefly, before CAL flashes. The concentration value based on the
factory default calibration is shown.
5) Press or to adjust the reading to match the known
oxygen concentration value.
6) Press to confirm the calibration. The primary display will blink
briefly before returning to measurement mode.
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