User Guide

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18
CALIBRATION
TURBIDITY CALIBRATION
The meter should be properly calibrated with
a standard prepared as described in USEPA
method 180.1.
Span calibration
To calibrate the span of the meter,
fill the cuvet with the primary turbid-
ity formazine standard of 50 NTU.
Inspect and clean thoroughly the sur-
face of the vial.
Shake the standard vigorously for a
few seconds and wait a few minutes
for the bubbles to disappear.
Turn the meter on and press both ALT and
CAL momentarily.
The LCD will show four
dashes on the upper
and “d 00” on the lower
part of the LCD with
the second “0” blinking.
Using the , and
keys change the lower
row of the display to
show “d 21”.
Insert the previously prepared 50 NTU stan-
dard into the cuvet holder and make sure that
the notch on the cap is positioned securely
into the groove. Press .
+
positioned securely into the groove. Press
READ.
The meter will first show “SIP” for a few
seconds and afterwards the sample concen-
tration: