Generator Set (Army). Instructions for operating the generator are contained in the applicable
generator set manual (TM 5-6115-465-12 for NSN 6115-00-118-1240).
b. Color Comparator Test Kit. Instructions to determine the pH values and chlorine residual in water
are contained in the color comparator test kit (para. 217, fig. 2-14). The Diethyl-P-Phenylene Diamine (DPD)
tablets are not part of the test kit, but are included in Storage Box No. 3.
TDS Meter (Portable). The TDS (total dissolved solids) meter is a calibrated meter that measures
how much electric current can flow through a sample of water. Pure water passes almost no current.
(1) Description of the TDS meter:
(a) Reads in ppm (parts per million) or in mg/l (milligrams per liter).
(b) Has three scales: 0 to 5 x 10,0 to 5 x 100, and 0 to 5 x 1000.
(c) Change scales with the range switch.
Figure 2-77. Total Dissolved Solids (TDS) Meter
Always start with meter set on the 0 to 5 x 1000 scale. If you use a lower scale
first, you may damage the meter.
The TDS meter is factory calibrated and suitable for use when treating fresh
(lake, stream, pond, river) water. When treating seawater and brackish water, it
is necessary to recalibrate the meter. If your meter has both 442 and NaCl
internal standards stamped on the bottom panel, obtain a standard sodium
chloride (NaCl) solution (ArmySC-4610-97-CL-E16; MC SL3-08580A)
and refer to subpara. (3).
(2) Recalibration instructions for meters with both internal standards (442 and NaCl) stamped
on the bottom of the meter: