Hach DR/850, Procedures Manual, Page: 142 / 460

142
5.
Wipe the outside of
the blank vial with a
towel.
Note: Wiping with a damp
cloth followed by a dry one
removes fingerprints and
other marks.
6.
Place the blank in the
adapter.
Push straight down on
the top of the vial until it
seats solidly into the
adapter.
Note: Do not move the vial
from side to side as this can
cause errors.
7.
Cover the vial tightly
with the instrument cap.
Press
:
ZERO
The cursor will move to
the right, then the
display will show:
0.00 mg/L Cl2
Note: If Reagent Blank
Correction is on, the
display may flash “limit”.
See Section 1.
8.
Remove the cap from
a Total Chlorine DPD-
TNT tube. Add
10 mL of sample.
Note: Fill to the top of the
Hach logo “oval” mark.
Note: A pink color will
develop if chlorine is
present.
9.
Cap and invert at
least 10 times to dissolve
the powder. This is the
prepared sample.
Note: Use slow, deliberate
inversion for complete
recovery. Ten inversions
should take at least
30 seconds. One inversion
equals turning the vial
upside down, then
returning it to an upright
position.
10.
Press:
TIMER ENTER
A three-minute reaction
period will begin.
Note: A pink color will
develop if chlorine
is present.
11.
When the timer
beeps, wipe the prepared
sample vial with a towel,
then place it in the vial
adapter.
Push straight down on
the top of the vial until it
seats solidly into the
adapter.
Note: Do not move the vial
from side to side as this can
cause errors.
12.
Cover the vial
tightly with the
instrument cap.
Press:
READ
The cursor will move to
the right, then the result
in mg/L total chlorine
will be displayed.
CHLORINE, TOTAL,
continued