Hach DR/700 Procedures Manual page 320

VOLATILE ACIDS,
19.
Press:
ZERO
The display will
count down to 0.
Then the display will
show 0 mg/L and the
zero prompt will turn
off.
22.
Press:
READ
The display will
count down to 0.
Then the display will
show the results in
mg/L volatile acids
(HOAc).
Note: Read the
prepared sample at
3 minutes as noted in
Step 13.
continued
20.
Pour 10 mL of
the prepared sample
into a 10-mL round
sample cell. Cap.
50-70
21.
Place the
prepared sample in
the cell holder.
Note: In bright light, it
may be necessary to
close the cell
compartment cover.