12
• Before inserting the vial into the
instrument, wipe it clean with
HI 93703-70 or a soft, lint-free
tissue. Handle vials so that no fin-
gerprints are left on the areas where
light passes through, that is the
bottom 2 cm (3/4”).
STANDARD SUSPENSION
Presently, there are only two recognized primary standards: AMCO-AEPA-1
(available through Hanna) and formazine. LP 2000 works with both
solutions.
AMCO-AEPA-1 has a much longer shelf life at all concentrations
(approximately six months, if free from contamination). In addition,
no special handling or disposal is required and a much higher
stability of suspended particles has been observed.
Formazine is highly toxic and is generated by a known carcinogen,
with poor stability (particles settle quickly). Lower concentrations
change value quickly after dilution.
The consistency of LP 2000 readings by using both standards has
been separately established by Advanced Polymer Systems and
Hanna Instruments.
Additional documentation about the formazine standard and other
calibration procedures is available upon request.
VIEWING THE CALIBRATION DATE
• Turn the meter on and wait for the
display to show "----".
• Press and hold the DATE/ key. The month and day of last
calibration ("MM.DD") appear while the key is held down.
Note: The displayed date is the date that was input by the user at
the beginning of the last calibration.
