User Instructions

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OUR MEASUREMENT
16. OUR MEASUREMENT
The OUR is used to determine the oxygen consumption or respiration rate in water. 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 test remember to set the OUR configuration from the Setup menu.
This a an example of possible setting. Follow your normal SOP.
Make sure the DO probe has been calibrated before using. Clean off probe between samples.
Press MODE to select the OUR measurement mode. Place the calibrated probe into the airtight
container of sample. Stir the sample. Press Start to begin taking measurements.
During the analysis the meter will display the ongoing calculation.
OUR recall: