Hanna Instruments HI 2400 - Manual (Page 9)

9
SALINITY AND ALTITUDE COMPENSATION
If the sample contains significant concentration of salinity or if you are
performing measurements at an altitude different from sea level, the
read out values must be corrected, taking into account the lower degree
of oxygen solubility in these situations (see pages 15-16).
Remember to set the altitude and/or the salinity before taking any DO
measurements. The meter will automatically compensate for these factors.
DO MEASUREMENTS
Make sure that the instrument has been calibrated and
the protective cap has been removed.
• Submerse the tip of the probe in the sample to be
tested. Allow approximately one minute for the reading
to stabilize.
• The Dissolved Oxygen value (in %) is displayed on the primary LCD
and the temperature on the secondary LCD.
• Press RANGE to change the reading from % to ppm and vice-versa.
For accurate Dissolved Oxygen measurements, a water movement of
0.3 m/s is required. This is to ensure that the oxygen-depleted
membrane surface is constantly replenished. A moving stream will
provide adequate circulation.
The use of a magnetic stirrer to ensure a certain fluid velocity is
recommended.
For an accurate calibration, it is recommended to wait at least 15 minutes
to ensure precise conditioning of the probe.
Keep the protective cap on during polarization time and remove it for
calibration and measurements. Follow the calibration procedure (see
page 10).