5. Rinse a clean tube (0290)
three times with the blank.
If samples are expected to
read below 1 NTU the meter
should be blanked with a 0
NTU Primary Standard or
prepared turbidity-free (<0.1
NTU) water. For the most
accurate results, use the
same tube for the blank and
the sample.
l
6. Fill the tube to the fi ll line with
the blank. Pour the blank
down the inside of the tube to
avoid creating bubbles. Cap
the tube.
7. Wipe the tube thoroughly with
a lint-free cloth.
8. Open the meter lid. Insert the
tube into the chamber. Align
the index line on the tube with
the index arrow on the meter.
Close the lid.
38
Calibration
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