Hach DR/850, Procedures Manual, Page: 381 / 460

381
17.
Press:
TIMER ENTER
A 2-minute waiting
period will begin.
Note: Read samples
between 2 and 8 minutes
after the addition of the
PhosVer 3 reagent.
Note: A blue color will
form if phosphate is
present.
18.
After the timer
beeps, clean the outside
of the sample vial with
a towel.
Note: Wiping with a damp
towel, followed by a dry
one, will remove
fingerprints or other marks.
19.
Place the prepared
sample vial 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.
20.
Tightly cover the
vial with the instrument
cap.
21.
Press:
READ
The cursor will move to
the right, then the result
in mg/L phosphate
(PO
4
3-
) will be
displayed.
Note: Standard Adjust may
be performed using a
prepared standard (see
Section 1).
IMPORTANT NOTE:
The test range for total
phosphate is limited to
0 to 3.5 mg/L PO
4
3-
.
Values above 3.5 mg/L
may be used to estimate
dilution ratios, but
should NOT be used for
reporting purposes. If a
value above 3.5 mg/L
PO
4
3-
is obtained, dilute
the sample and repeat
the digestion and the
colorimetric test.
PHOSPHORUS, TOTAL,
continued