TM 10-4320-317-13
(7)
Add two DPD No. 1 tablets and crush with the plastic rod (5).
(8)
Fill this cell to the mark (6) with the water under test and insert it in the left hand cell space (7) of the
comparator (3). Compare with the color standards of the appropriate disc as rapidly as possible. Record the
result which is the closest match as the value of the free residual chlorine level of the test sample.
Interpolation between two values may be necessary.
d. Perform chloride pH test as follows (Figure 2-31):
Figure 2-31. Chloride pH Test
(1)
Place the pH color disc (1) in the comparator (2).
(2)
Rinse and fill two dean cells (3) with water sample to the mark (4).
(3)
Hold the comparator (2) with the eye piece facing you and place the two water-filled cells (3) into the openings
at the top.
(4)
Fill the dropper (1, Figure 2-32) of the wide range indicator solution (white cap) bottle to the 0.50 mL mark (2).
Figure 2-32. pH Test Cell
2-54
