YSI ProDSS Meter Calibration and Maintenance
K:\Streamkeepers\Monitoring\Eqpt & supplies\Calibration-Maintenance\SOPs\YSI ProDSS maint-
cal SOP's
13
Turbidity Calibration
For proper calibration, you must use standards that have been prepared according to details in
Standard Methods for the Treatment of Water and Wastewater (Section 2130 B).
The standard Streamkeepers uses is:
YSI 6073G Turbidity Standard
124 FNU
– for an EXO Turbidity Sensor
Do not use any other standards or it will result in calibration errors and inaccurate field readings.
Never mix standards together, i.e. formazin and the above standard
This standard will expire 1 year after opening!
If you open a fresh gallon of the YSI 6073G
turbidity standard, write the date it was opened on the label in permanent marker
Equipment Needed:
•
“Turbidimeter Calibration Protocol & Data Sheets” notebook
•
YSI ProDSS
•
YSI 6073G turbidity standard (124 FNU)
Calibration:
NOTE: The sensor guard must be installed on the unit to calibrate the turbidity sensor. When
calibrating turbidity, the first point
must
be zero. The following is a 2-point calibration with
clear deionized water, and the turbidity solution.
1.
Make sure that the sensors and calibration cup have been rinsed2-3 times with distilled or
clean tap water since the previous calibration procedure (should have been pH).
2.
Rinse the sensors and calibration cup with “zero standard”, or deionized water. Shake off the
unit and cup after rinse.
3.
SLOWLY
pour the deionized water down the side of the cup (like you’re pouring a beer),
fill the cup to the first fill line (170 mL). Immerse the sensors
and the guard
into the cup.
A few air bubbles are ok but you don’t want a lot.
4.
Select the
calibration button
, then select Turbidity.
5.
Select Calibration Value and enter 0.0 (if it isn’t already).
6.
Confirm stabilization by watching the
actual readings
on the screen, if there is no significant
changes to the readings for 40 seconds, the sensor is stable.
7.
After observing stabilization, press Accept Calibration. “Ready for cal point 2” will be
displayed in the message area, you are now ready to calibrate the second point.
DO NOT
back out to the “Run” screen by hitting the left arrow button, or the Esc button. If
you don’t finish the two point calibration, the unit will register this as a one point calibration
and you will have to start over again with the turbidity calibration.
8.
If you open a new YSI turbidity standard, write the date on the label in permanent
marker.
9.
Rinse sensors once with distilled water, once with old buffer solution (if available, if not use
distilled water again), and twice with new solution. To rinse, fill cup ~2”, attach cup to unit
and lightly shake the unit while tilting it back and forth. Shake and tilt the unit until all
sensors and guard have been rinsed.
10.
SLOWLY
pour the standard down the side of the cup (like your pouring a beer), fill the cup
