Hach Lange 2100AN Basic User Manual page 12

• Ratio-on and Ratio-off calibration data is measured and recorded at
the same time.
• The 7500-NTU standard does not have to be measured during
calibration if turbidity less than 4000 NTU will be measured. Push
CAL/Zero after the 4000 NTU standard is measured to complete the
calibration procedure.
StablCal calibration procedure
1. Remove the filter 2. Clean the lens of the
assembly. Refer to USEPA filter assembly.
Change the filter Refer to
assembly on page 16. assembly
12 English
3. Hold the tab of the
USEPA filter assembly
Clean the filter so that the arrows point
on page 17. toward the front of the
instrument. Push the
filter assembly fully in
the housing.
• Clean the USEPA filter assembly before doing a primary calibration,
or at least every 3 months (which is the USEPA-recommended
primary calibration interval).
4. Push CAL/Zero. 5. Get the < 0.1 NTU
vial. Clean the vial with
The CAL/Zero light
a soft, lint-free cloth to
turns on, and the mode
remove water spots and
display shows "00". The
fingerprints. Do not
NTU value of the
invert the vial.
dilution water that was
used in the previous
calibration is shown on
the display.
6. Apply a small bead
of silicone oil from the
top to the bottom of the
vial.