Hach DR/700 Procedures Manual page 682

PHOSPHONATES,
10.
Add the
contents of one
PhosVer 3 Phosphate
Reagent Powder
Pillow to each sample
cell. Cap and invert
several times to mix.
Note: A blue color will
develop if phosphate,
produced by the
digestion, is present.
Note: A 10-mL sample
can be tested by using
10-mL sample cells and
optional reagents.
continued
2 minutes
11.
Wait 2 minutes.
Note: If the sample is
o
colder than 15 C, 4
minutes are required for
color development.
81-8
12.
Place the blank
in the cell holder.
Note: Use a 10-mL cell
for the blank and
sample in bright
sunlight and close the
cell compartment cover.
Note: Perform Steps 13
and 14 within three
minutes after the two-
minute period.