TM 10-4320-303-13
2.5.5.7 Performing Chlorine Residual Tests. (Continued)
CAUTION
DO NOT hold comparator to direct sunlight or artificial light when comparing colors. Test
results will not be correct.
DO NOT cover light window in rear of body.
k. Hold the comparator (Figure 2-52, 1) to your eye and face a good light source (daylight but not the
direct rays of the sun, daylight illuminator or artificial light reflected from a white surface). Look
through the prism eyepiece (2) at a distance of about 10 inches (3).
l. Rotate chlorine color disk (Figure 2-49, 4) until a color on the disc matches the color on the left hand
sample cell or indicator cell (Figure 2-51, 4). The readings can be made directly from the number
display window (Figure 2-49, 6). The value is expressed in milligrams per liter (mg/l).
m. Record value number shown in number display window (Figure 2-49, 6). If color of indicator cell
(Figure 2-51, 4) is between colors on the chlorine color disk (Figure 2-49, 4), the value number must
be estimated.
n. The readings must be made within one minute of adding the chemicals to the indicator cell.
o. When test has been completed, empty the samples and wash the sample cells; (Figure 2-51, 1 and 4)
with clean water.
p. Remove prism eyepiece (Figure 2-50, 1) and place in kit container.
q. Remove two screws (Figure 2-49, 1) and front cover (2) on comparator body (3). Remove chlorine
color disc (4) and place in kit container.
r. Place front cover (2) on comparator body (3). Install and tighten screws (1) Place color comparator (1,
2, and 3) in kit container. Fasten latch on kit container.
s. Store kit in metal box mounted on hypochlorination unit skid.
2.5.5.8 Performing PH Test.
a. Refer to paragraph 2.5.5.7 and perform steps a through f, ensuring that either the WIDE RANGE
INDICATOR-D or pH disc is installed.
CAUTION
Make sure correct disc is used for pH test. Tag on disc should either read WIDE RANGE
INDICATOR-D or pH.
If wrong disc is used, test results will beincorrect.
b. Fill the dropper (Figure 2-53, 1) of the wide range indicator solution white cap) bottle to the 0.50 ml
mark (2).
c. Using the dropper (1) add the indicator solution to the sample cell (3) in the left-hand cell space
(Figure 2-51, 4) only. (Water sample without indicator solution in right opening compensates for
color and turbidity.)
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