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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 tur-
bidity formazine standard of
50 NTU.
Inspect and clean thoroughly the
surface of the vial.
Shake the standard vigorously for
a few seconds and wait a few
minutes for the bubbles to disap-
pear.
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 se-
curely into the groove.
Press
.
Insert the reacted sample into the cuvet holder
and make sure that the notch on the cap is
positioned securely into the groove. Press
READ.
The meter will first show “SIP” for a few
seconds and afterwards the sample concen-
tration:
+