Hach POCKET COLORIMETER II Instruction Manual page 25

7.
Cap and shake gently for
20 seconds.
Shaking dissipates
Note:
bubbles that may form in
samples with dissolved
gases.
Note: A pink color will
develop if chlorine is
present.
Chlorine, Free and Total, LR,
8.
For free chlorine, place
the prepared sample cell in
the cell holder and cover
with the instrument cap.
Proceed to step 10 within
one minute after adding the
DPD Free Pillow.
Accuracy is not
Note:
affected by undissolved
powder.
Wipe off sample
Note:
cells.
1—25
continued
9.
For total chlorine,
place the prepared sample
in the cell holder and cover
with the instrument cap.
Wait three to six minutes
after adding the DPD Total
Pillow.
Proceed to step 10.