Hanna Instruments HI 95771 - Manual (Page 12)

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The instructions listed below should be carefully followed during testing to ensure best accuracy.
• For a correct filling of the cuvet: the liquid in the
cuvet forms a convexity on the top; the bottom of
this convexity must be at the same level of the 10
mL mark.
• Proper use of the powder reagent packet:
(a) use scissors to open the powder packet;
(b) push the edges of the packet to form a spout;
(c) pour out the content of the packet.
GENERAL TIPS FOR AN ACCURATE MEASUREMENT
(a) (b) (c)
• It is important that the sample does not contain any
debris. This would corrupt the reading.
• Each time the cuvet is used, the cap must be
tightened to the same degree.
• Whenever the cuvet is placed into the measurement
cell, it must be dry outside, and completely free of
fingerprints, oil or dirt. Wipe it thoroughly with
HI 731318 or a lint-free cloth prior to insertion.
• Shaking the cuvet can generate bubbles in the sample,
causing higher readings. To obtain accurate
measurements, remove such bubbles by swirling or
by gently tapping the vial.
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• Do not let the reacted sample stand too long after reagent is added, or accuracy will be lost.
• It is possible to take multiple readings in a row, but it is recommended to take a new zero
reading for each sample and to use the same cuvet for zeroing and measurement.
• After the reading it is important to discard immediately the sample, otherwise the glass
might become permanently stained.
• All the reaction times reported in this manual are referred to 20°C (68°F). As a general rule
of thumb, they should be doubled at 10°C (50°F) and halved at 30°C (86°F).
• In order to maximize accuracy, prior to a measurement follow the validation procedure to
be sure that the instrument is properly calibrated. If necessary, calibrate the instrument.
OPERATIONAL GUIDE
• Turn the meter on by pressing ON/OFF.
• When the LCD displays “771” is ready: the Chlorine ULTRA HIGH
RANGE scale is automatically selected each time the instrument is
turned on.
• To change parameter keep ZERO/SET pressed. The parameter code
will change every three seconds, until the key is released. Select the
program for “771” for chlorine ULTRA HIGH RANGE or “701” for
chlorine LOW RANGE
• After the desired parameter code appears on the display, perform
either MEASUREMENT, VALIDATION, or CALIBRATION PROCEDURE
following the instructions reported in the related chapter.
Code Parameter
771 Chlorine Ultra High Range
701 Chlorine Low Range
or
Important Note: chlorine ULTRA HIGH RANGE and chlorine LOW
RANGE have to be measured separately with fresh unreacted samples
if both values are requested.