Hach-Lange 2100 N Laboratory Turbidimeter User Manual - Manual (Page 17)

Measure the Gelex secondary turbidity standards
Measure the Gelex secondary turbidity standards each time the instrument is calibrated and record the new values on the Gelex vials with a water
soluble marker.
1. Clean the Gelex
vials with a soft, lint-free
cloth to remove water
spots and fingerprints. 2. Apply a small bead
of silicone oil from the
top to the bottom of the
vial. 3. 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. 4. Push RANGE to
select automatic
ranging.
The Auto Range light
turns on. 5. Push SIGNAL AVG
to turn signal averaging
off.
The SIGNAL AVG light
turns off. 6. Push UNITS/Exit to
select the NTU
measurement mode.
The NTU light turns on.
English 15