contact for a specified time (10 minutes). The
dotted line 1. A vertical line dropped from the in-
tersection to the lower half of the chart gives the
dosage is determined from the calculation and
volumes of various solutions necessary to achieve a
based on the fact that 8.3 pounds of chlorine per
million gallons of water represent one part of
3 ppm treatment. We find that the treatment can be
chlorine in a million parts of water. Chlorine
obtained with about 18 gallons per day of 2 percent
residual is determined by measurement by color
solution : With 35 gallons per day of 1 percent
comparator and is the final check on proper
solution; or with about .58 gallons per day of .6
chlorination.
percent solution. If the hypochlorinator runs at a
(4) The use of the chart is most readily ex-
speed of 12 strokes per minute, it will pump 18
plained by taking an example. Suppose that it is
gallons per day when the stroke control is set at 3;
desired to add 3 ppm of chlorine to a water flow of
36 gallons per day at a setting of 6; and 60 gallons
80 gpm. on the upper left-hand portion of the
per day at a setting of 10.
chart, we find the line corresponding to 80 gpm and
run horizontally to the line marked 3 ppm (note
