Hach-Lange 2100 AN IS Laboratory Turbidimeter User Manual - Manual (Page 41)

Formazin calibration procedure
For the best accuracy, use four matched sample cells or the same sample cell for all measurements during calibration. Refer to Matching sample cells
on page 21.
1. Push CAL/Zero.
The CAL/Zero light
turns on, and the mode
display shows "00" .
The NTU value of the
dilution water used in
the previous calibration
is shown. 2. Rinse a clean
sample cell two times
with dilution water. Fill
the sample cell to the
line (about 30 mL) with
dilution water and
immediately put the cap
on the sample cell. Use
the same dilution water
that was used to
prepare the formazin
standards. 3. Clean the sample
cell with a soft, lint-free
cloth to remove water
spots and fingerprints.
Do not invert the
sample cell. 4. Apply a small bead
of silicone oil from the
top to the bottom of the
sample cell. 5. Use the oiling cloth
provided to apply the oil
equally to the surface of
the sample cell.
Remove the excess oil.
Make sure that the
sample cell is almost
dry. 6. Put the sample cell
in the sample cell
holder with the triangle
on the sample cell
aligned with the
reference mark on the
sample cell holder.
Close the cover.
English 39