Hach-Lange 2100 N IS Laboratory Turbidimeter Basic User Manual - Manual (Page 10)

• All nephelometric (turbidity units of measure) calibrations are done at
the same time.
• The 4000-NTU standard does not have to be measured during
calibration if FNUs will be measured. Push CAL after the 1000 NTU
standard is measured to complete the calibration procedure.
• The FNU values of StablCal standards and formazin standards are
calculated using the conversion factors of 1 FNU = 1 NTU.
StablCal calibration procedure
1. Push CAL.
The S0 light turns on.
The NTU value of the
dilution water used in
the last calibration is
shown on the display. 2. Get the < 0.1 NTU
vial. Clean the vial with
a soft, lint-free cloth to
remove water spots and
fingerprints. Do not
invert the vial. 3. Apply a small bead
of silicone oil from the
top to the bottom of the
vial. 4. Use the oiling cloth
to apply the oil equally
to the surface of the
vial. Remove the
excess oil. Make sure
that the vial is almost
dry. 5. Put the vial in the
sample cell holder with
the triangle on the vial
aligned with the
reference mark on the
sample cell holder.
Close the cover. 6. Push ENTER.
The instrument display
counts down, then
measures the standard.
The next expected
standard (e.g., 20.00) is
shown. The S1 light
turns on.
10 English