Basic HTML Version
SOP5 – WQ Instrumentation
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Under the Calibrate menu choose ISE1pH>2 and 2-point. Calibrate pH 7 first. When prompted
type in ‘7’ and hit Enter. Allow at least 1 minute for stabilization of temperature and pH probes
then record the precal pH and pH-mV readings. Hit Enter again, then record the postcal pH and
pH-mV readings. Proceed to calibrating pH 10. When prompted type in ‘10’ and hit Enter. Allow
at least 1 minute for stabilization of temperature and pH probes then record the precal pH and
pH-mV readings. Hit Enter again, then record the postcal pH and pH-mV readings. Rinse the
sensors with DI water.
6.3.4. Chlorophyll
MERC uses DI water to calibrate the sensors for chlorophyll analysis. Fill calibration cup with
enough DI water to submerge the chlorophyll and temperature sensors. Sample rinse the sensors
with DI water. Attach calibration cup with standard onto the sonde and run the calibration
procedure in EcoWatch.
Under the Calibrate menu choose Optic-C Chlorophyll, then Chl µg L
-1
, and then 1-point. When
prompted type in ‘0’ and hit Enter. Hit 3 to activate wipers (may need to hit more than once).
Allow at least one minute after wipers have finished for stabilization before recording the precal
value. Hit Enter again and record the postcal reading. Record temperature. Rinse the sensors with
DI water.
6.3.5. Turbidity
MERC uses YSI Incorporated polymer-based 126 NTU turbidity solution for the standard. Fill
calibration cup with enough standard or DI water so the turbidity sensor is submerged. Calibrate
with DI water first. Sample rinse the sensors with DI water. Attach calibration cup with DI water
onto the sonde and run the calibration procedure in EcoWatch.
Under the Calibrate menu choose “Optic-T Turbidity-6136/6026” 2 point. When prompted, type
in ‘0’ and hit Enter. Type in the number 3 to activate wipers. Allow at least 1 minute for
stabilization before hitting Enter and recording the readings. Hit enter again so you can proceed
to the next calibration point.
Sample rinse the sensors with solution used during last calibration procedure. Attach calibration
cup with standard onto the sonde and continue with the calibration procedure. When prompted
type in ‘126’ and hit enter. Allow at least 1 minute for stabilization. When stable, record the
precal reading then hit Enter and record the postcal reading. Rinse the sensors with DI water.
6.3.6. Dissolved Oxygen
Pour a small amount DI water into the bottom of a calibration cup to cover the bottom. Place the
calibration cup in a bucket and place the sonde into the cup. Do not tighten. Under the Calibrate
menu choose Dissolved Oxy then DOsat%; enter the barometer reading in mm Hg and hit Enter.
When the readings are stable record the precal reading then hit Enter and record the postcal
reading.