Hach DR/850, Procedures Manual, Page: 72 / 460

72
9.
The display will
show: 00:30 Timer 2
Press:
ENTER
A thirty-second reaction
period will begin.
Vigorously shake the
cylinder for the 30-
second period.
Note: This solution should
turn a light to medium
orange upon bleaching. It
will not become colorless.
10.
Pour the 25 mL of
mixture in the cylinder
into a second 25-mL
sample cell (the blank).
11.
The display will
show: 15:00 TIMER 3
Press:
ENTER
A 15-minute reaction
period will begin.
12.
Within three
minutes after the timer
beeps, place the blank
into the cell holder.
Tightly cover the sample
cell with the instrument
cap.
13.
Press:
ZERO
The cursor will move to
the right, then the
display will show:
0.000 mg/L Al
Note: If Reagent Blank
Correction is on, the
display may flash “limit”.
See Section 1.
14.
Immediately place
the prepared sample into
the cell holder. Tightly
cover the sample cell
with the
instrument cap.
15.
Press:
READ
The cursor will move to
the right, then the result
in mg/L aluminum will
be displayed.
Note: Clean the graduated
cylinder and sample cells
with soap and brush
immediately following
the test.
Note: Standard Adjust may
be performed using a
prepared standard (see
Section 1).
ALUMINUM,
continued