Hach DR/700 Procedures Manual page 540

QUATERNARY AMMONIUM COMPOUNDS, continued
7.
Fill a 25-mL cell
to the 25-mL line
with sample.
2 minutes
10.
Wait 2 minutes.
8.
Add the contents
of one Q.A.C. Reagent
1 powder pillow. Cap
and invert to mix.
Remove cap after
mixing.
Note: Shaking the cell
will cause air bubble
turbidity which
dissipates slowly and
interferes with test
results.
11.
Place the blank in
the cell holder.
Note: Typical indoor
lighting permits the
DR/700 to operate with
the cell compartment
cover open. In bright
sunlight it may be
necessary to close the
cell compartment cover.
Transfer 10 mL of the
blank solution to a
10-mL cell. If the 10-mL
cell is used for the blank,
another 10-mL cell must
be used for the sample.
57-34
9.
Add the contents
of one Q.A.C.
Reagent 2 powder
pillow. Cap and
invert to mix.
12.
Press:
ZERO
The display will
count down to 0.
Then the display will
show 0.0 mg/L and
the zero prompt will
turn off.