User Guide

19
* 1 FTU = 1 NTU
STANDARD SUSPENSION
Presently, there are only two recognized pri-
mary standards: AMCO-AEPA-1 and formazine.
Hanna supplies HI 93703-11 with the AMCO-
AEPA-1 which has a much longer shelf life at all
concentrations (approx. 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 ob-
served.
On the other hand, formazine is a toxic sub-
stance, generated by a known carcinogen, with
poor stability (particles flocculate and settle
quickly). Lower concentrations change value
within a few days or hours after dilution.
The consistency of HI 93703-11 readings by
using both standards has been separately es-
tablished by Advanced Polymer Systems and
Hanna Instruments.
Additional documentation about the formazine
standard and more complex calibration proce-
dures is available upon request.
• All glassware that comes into contact with
standards should be maintained clean. Wash
with the HI93703-50 cleaning solution and
rinse with HI 93703-0 or turbidity free water.
• Rinse the vial twice with 5 ml of the liquid to
be tested. This removes the effect of any
previous liquid and any dust or foreign ob-
jects that may be present inside. Gently pour
the liquid down the side of the vial to reduce
air bubbles (no mixing is required when HI
93703-0 and HI 93703-10 AMCO-AEPA-1
standards are used).
• Before inserting the vial into the instrument,
wipe it with HI93703-70 or a soft, lint-free
tissue. Handle vials so that no fingerprints
can get on the areas where light passes
(approx. bottom 2 cm/1").
20
BATTERY REPLACEMENT
All components have been selected to mini-
mize current drain without compromising func-
tionality. In order to minimize the battery con-
sumption, the meter is equipped with an auto-
shut off function which switches the meter off
after 5 minutes of non-use.
The power source is 4 x 1.5V batteries with an
expected life of 60 hours, or 900 measure-
ments.
In order to obtain accurate measurements, the
batteries are monitored every time the meter is
switched on.
In addition, a "LO BAT" indication will appear on
the lower right hand side of the display when the
batteries are weak (<10%). Replace all four
batteries at this point.
When the batteries are too weak to perform
measurements, the message 0% LO BAT ap-
pears for a few seconds, and then the meter will
automatically switch itself off. At this point, the
batteries must be replaced.
LOBAT
0
%
LO BAT