Hanna Instruments HI 4421 - Manual (Page 45)

45
The OUR is used to determine the oxygen consumption or respiration rate. It is defined as the mg/L of oxygen
consumed per hour.
The following equation is used for OUR determination:
where:
DO
START
= Dissolved oxygen level at start of test
DO
END
= Dissolved oxygen level at end of test
t
ELAPSED
= Elapsed time of test in seconds
total volume/sample volume = Dilution factor of sample
Before starting an OUR measurement remember to set the OUR configuration from the OUR setup menu and make
sure the instrument has been calibrated on DO.
To measure the OUR of a sample:
• Press
and then to select OUR measure mode.
• Press to start taking the measurement.
• At the end of the measurement the meter will display the
computed OUR value, the duration of the measurement and
the pressure and temperature values.
OUR MEASURE OUR MEASURE OUR MEASURE OUR MEASURE OUR MEASUREMENT MENT MENT MENT MENT