Hach-Lange 2100 N IS Laboratory Turbidimeter User Manual - Manual (Page 32)

Table 5 Formazin standard preparation
Standard Step 1 Step 2 Step 3
20 NTU Add 100 mL of
dilution water to a
clean 200-mL Class
A volumetric flask.
Refer to
Prepare
dilution water
on page 20.
With a TenSette ®
Pipet, add 1.00 mL of
well-mixed 4000-NTU
formazin stock
solution to the 200-
mL flask.
Dilute to the mark
with dilution water.
Stopper and mix.
200 NTU Add 50 mL of dilution
water to a clean 100-
mL class A
volumetric flask. With a TenSette 1
Pipet, add 5.00 mL of
well-mixed 4000-NTU
formazin stock
solution to the 100-
mL flask.
Dilute to the mark
with dilution water.
Stopper and mix.
1000 NTU Add 50 mL of dilution
water to a clean 100-
mL class A
volumetric flask.
With a TenSette 1
Pipet, add 25.00 mL
of well-mixed 4000-
NTU formazin stock
solution to the 100-
mL flask.
Dilute to the mark
with dilution water.
Stopper and mix.
1 A class A volumetric pipet may be used in place of a TenSette Pipet.
Calibration notes
• Make sure that the instrument is in the same ambient conditions as
where it is used.
• Make sure that the standards are at the same ambient temperature as
the instrument before use.
• Use only the provided silicone oil. This silicone oil has the same
refractive index as the vial glass and masks minor glass differences
and scratches.
• Store the oiling cloth in a plastic storage bag to keep the cloth clean.
• If power is lost during calibration, the new calibration data is lost and
the last calibration data is used. To exit a calibration and not save the
new values, push UNITS/Exit.
• In Calibration mode, automatic range and signal averaging on are
selected. When calibration is completed, all operational modes go
back to the last settings.
• 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.
30 English