user manual

TAKING MEASUREMENTS:
Verify the probe is polarized and the probe and
meter have been calibrated. Remove the protective
cap from probe. Immerse the tip of the probe in
the sample to be tested.
For accurate dissolved oxygen measurements a
minimum water movement of 0.3 m/sec is required.
This is to ensure that the oxygen-depleted
membrane surface is constantly replenished. A
moving stream will provide adequate circulation. To quickly
check if the water speed is sufficient, wait for the reading to
stabilize and then move the D.O. probe. If the reading is still
stable, the measurement conditions are right, while if the reading
increases, the water movement is not adequate.
During field measurements, this condition may be met by manually
agitating the probe. Accurate readings are not possible while
the liquid is at rest.
During laboratory measurements, the use of a magnetic stirrer
to ensure a certain velocity in the fluid is recommended. In this
way, errors due to the diffusion of the oxygen present in the air
into the solution are reduced to a minimum.
Always wait for thermal equilibrium to occur between the probe
and the sample before recording a measurement (a few minutes
for temperature difference of several degrees).
ALTITUDE & SALINITY COMPENSATION:
If the sample contains salts or if you are performing the
measurements at a higher altitude, the displayed reading must
be corrected to account for the lower degree of oxygen solubility.
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