WWA Volunteer Monitoring Program
SOP ID Number: 402
Revision Date: 9/7/16
Revision Number: 1
Issue Date: 9/27/16
Orion Star A329 Dissolved Oxygen Calibration Check and Field Measurement
Approved by:
______________________________
WWA Director
Reviewed by:
______________________________
Volunteer Monitoring Coordinator
FIELD CALIBRATION CHECK
1. Gently take the white calibration tube off of the DO probe and remove sponge located under
cap in tip of probe.
2. Saturate the sponge with water (use the deionized, DI, water bottle provided). Squeeze the
excess liquid from the sponge and replace sponge into white calibration tube.
3. Allow a minimum of ten minutes for the moist air in the chamber to reach a steady state.
4. After ten minutes, Press the
(power/light) key to turn the Orion A329 meter on. This will
automatically bring you to the measurement screen:
- Note: Press f3 (Channel) to toggle screen options (you can complete just the DO field
calibration check using any measurement screen that shows DO % or you can complete
all field calibration checks using the measurement screen as shown above)
Page 1 of 3
WWA Volunteer Monitoring Program
SOP ID Number: 402
Revision Date: 9/7/16
Revision Number: 1
Issue Date: 9/27/16
key. Wait for the reading to stabilize (Stabilizing…. Ready AR)
will begin flashing on the screen. When the reading has stabilized, Ready AR will stop flashing.
5. Press the measure
6. Record the stabilized reading on the DO section of the field datasheet (Form VM2000M).
Record the temperature and both DO mg/L and DO % concentration values.
7. For an acceptable calibration check % DO must be between 90% - 110%. If calibration check
is not acceptable, correct any obvious problems and repeat calibration check.
8. Repeat twice more for a minimum of three (3) readings and record these readings on the Field
datasheet.
DO SAMPLE MEASUREMENT
Important Note: Prior to taking DO sample measurements, ensure that the probe has had
sufficient time (usually 5-10 minutes at a minimum) to acclimate to water temperature.
This is usually accomplished by obtaining a sample and letting the probes rest in the
sample water for 5-10 minutes then replacing the sample water prior to taking sample
measurements. DO probe will take longer than the conductivity probe to acclimate. Use the
screen option that displays the three parameters to be sure probes are acclimated to sample
water temperature.
1. If meter power is off, turn power on by pushing the
(power/light) key. If you don’t see
DO on the screen, press the f3 key to toggle to a screen with the Dissolved Oxygen (DO)
measurement display.
2. Remove the probe from the white storage chamber and screw on the silver protective sleeve.
Place the probe into the sample for acclimation.
3. After acclimation (also called equilibration or conditioning), get a fresh batch of water to
make measurements.
4. Press the measure
key. The DO value may fluctuate while the reading is
stabilizing. Allow the reading to stabilize. When the reading has stabilized, Ready AR will stop
flashing.
5. Once stabilized, record both DO mg/L and DO % concentration values and temperature
(toggle between the DO% and DO mg/L modes by pushing the mode key).
6. Record the DO values on the field datasheet. At least three readings are required so press
READ/enter again, let it stabilize, and record the readings on the datasheet at least two more
Page 2 of 3
WWA Volunteer Monitoring Program
SOP ID Number: 402
Revision Date: 9/7/16
Revision Number: 1
Issue Date: 9/27/16
times for a minimum of three readings. Watch for drift in the last two readings and, if the criteria
are not met, repeat readings until these are met.
7. After completing at least three DO readings (both % and mg/L), turn the meter off. Remove
the probe from the sample, and remove the protective silver sleeve. Rinse the probe with DI
water and wipe the excess water off.
8. Insert the DO probe into the white storage chamber.
9. You have now completed all DO readings.
REVISION HISTORY
SOP
Revision #
1
Revision Date
Section Modified
Modification
Reason Changed
All
Added header/footer to
include program name, SOP
number, revision
date/number, issue date, and
page numbering. Added
approval sign offs and
revision history sections.
Updating for better document
control.
All
Proofreading edits by
Christine Ellis
To improve clarity and fix
typos.
9/7/16
Page 3 of 3