Hach DR/850 Procedures Manual page 179

FLUORIDE,
continued
5.
Cap and quickly
invert the ampules
several times to mix.
Wipe off any liquid or
fingerprints.
9.
Place the AccuVac
Ampul containing the
sample into the
instrument. Tightly
cover the sample cell
with the instrument cap.
6.
Press:
TIMER ENTER
A one-minute reaction
period will begin.
10.
Press:
READ
The cursor will move to
the right, then the result
in mg/L fluoride will be
displayed.
Note: Use of the Standard
Adjust feature with each
new lot of reagent is highly
recommended. See
Accuracy Check following
these steps.
7.
After the timer beeps
place the blank into the
cell holder. Tightly
cover the ampule with
the instrument cap.
179
8.
Press:
ZERO
The cursor will move to
the right, then the
display will show:
0.0 mg/L F