Hanna Instruments HI2400 Instruction Manual page 10

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 rec‑
ommended.
TEMPERATURE MEASUREMENTS
The probe has a built‑in temperature sensor.
The measured temperature is indicated on the secondary LCD as shown
above.
Allow the probe to reach thermal equilibrium before taking any measure‑
ment. This can take several minutes. The greater the difference between
the temperature at which the probe was stored and the temperature of
the sample, the longer the time will be.
Note: If "----" is displayed, the DO probe is not properly connected.
This also indicates the possibility of a broken probe cable. If the
temperature is displayed blinking, the temperature is out of range.
10