18
STANDARD SUSPENSION
Presently, there are only two recognized primary standards:
AMCO-AEPA-1 and formazine.
HANNA instruments supplies HI 93703
with the AMCO-AEPA-1
which has a much longer shelf life at all concentrations (approxi-
mately 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.
On the other hand, formazine is a very toxic substance, generated
by a known carcinogen, its stability is poor (particles flocculate and
settle quickly). Lower concentrations change value within a few
days or hours after dilution from stock solutions.
The consistency of HI 93703
readings by using both standards has
been separately established by Advanced Polymer Systems and
HANNA instruments.
Additional documentation about the formazine standard and more
complex 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 and a “MM.DD“ message
appears for few seconds
followed by the time.
To Next Page
Loading...
Need help?
General
