LaMotte MULTI-RANGE CONDUCTIVITY METER DA-1 1929 User Manual
Page 5
CONVERSION TABLE FOR
CHANGING CONDUCTIVITY* INTO SALINITY
If the temperature compensation knob was set to the sample temperature
when the conductivity reading was recorded, use the 25°C column to
receive the results as ppt salinity.
If temperature compensation was not used when you recorded the
conductivity reading (the temperature knob was set to 25°C), use the
column that reflects the actual sample temperature to receive results as ppt
salinity.
CONDUCTIVITY
SALINITY
0°C
5°C
10°C
15°C
20°C
25°C
30°C
0
00
1,200
1,400
1,500
1,700
2,000
2,200
2,400
1
2,220
2,500
2,900
3,300
3,700
4,100
4,500
2
3,200
3,700
4,200
4,700
5,300
5,900
6,500
3
4,100
4,700
5,400
6,100
6,900
7,600
8,400
4
5,000
5,800
6,600
7,500
8,400
9,300
10,300
5
5,900
6,800
7,900
8,800
9,900
11,000
12,100
6
6,700
7,800
8,900
10,100
11,300
12,600
13,900
7
7,600
8,800
10,100
11,400
12,800
14,200
15,700
8
8,500
9,800
11,200
12,700
14,200
15,800
17,400
9
9,300
10,800
12,300
13,900
15,600
17,300
19,100
10
10,200
11,800
13,400
15,200
17,000
18,900
20,800
11
11,000
12,800
14,500
16,400
18,900
20,400
22,500
12
11,900
13,700
15,600
17,600
19,700
21,900
24,100
13
12,600
14,600
16,700
18,900
21,100
23,400
25,800
14
13,400
15,600
17,800
20,100
22,400
24,900
27,400
15
14,200
16,400
18,800
21,200
23,800
26,400
29,100
16
15,000
17,400
19,800
22,400
25,100
27,800
30,700
17
15,800
18,300
20,900
23,600
26,400
29,300
32,300
18
16,600
14,200
21,900
24,800
27,700
30,700
33,900
19
17,400
20,100
23,000
25,900
29,000
32,200
35,500
20
18,200
21,100
24,000
27,100
30,300
33,600
37,000
21
19,000
22,000
25,100
28,300
31,600
35,000
38,600
22
19,800
22,900
26,100
29,400
32,900
36,500
40,100
23
20,600
23,800
27,100
30,600
34,200
37,900
41,700
24
21,400
24,700
28,100
31,700
35,400
39,300
43,200
25
22,100
25,500
29,100
32,800
36,700
40,700
44,800
26
22,800
26,400
30,100
33,900
37,900
42,100
46,300
27
*Conductivity values are given in micromhos/cm.
8
5.
Measure the temperature of the sample solution, set the “TEMP”
knob at the mark indicating the temperature. (Note the markings are
in centigrade.) Temperature has a pronounced effect upon
conductivity, and must be monitored accurately.
6.
Immerse the probe into at least ½" of solution. Make sure all bubbles
are removed from the probe.
7.
Switch the control knob to the “ON ” position and the range selector
to either “X1,” “X10,” “X100,” or “X1000.” Read the conductivity
directly from the meter face. For the best accuracy, select the range
which gives readings as close to mid-range of the scale as possible.
Multiply the reading from the meter face by the appropriate factor.
The probe should not be in contact with any surface other than the
solution being tested.
8.
After completing the conductivity measurement, switch control knob
to the “OFF” position. Rinse the probe thoroughly with water,
preferably distilled water, and drain.
9.
Reference solutions which have known conductivities may be
prepared by consulting the latest edition of Standard Methods for the
Examination of Water and Wastewater, American Public Health
Association, 1015 East Eighteenth Street, NW, Washington, DC
20036. A series of accurately prepared reference solutions in both the
high range and low range allow the operator to check on the
manipulative procedure as well as the verification of results.
DETERMINATION OF CONDUCTIVITY & TDS
IN BOILER WATER
In boiler water where high concentrations of hydroxides may be evident, it
is necessary to neutralize the sample solution with gallic acid or lactic acid.
Otherwise high conductivities will be noted. For a 100 mL sample add 0.4
grams of gallic acid or lactic acid. This will neutralize approximately 1300
ppm hydroxide alkalinity. If a small amount of gallic acid or lactic acid
does not dissolve within the sample solution, the conductivity reading will
not be affected. On some highly alkaline waters higher concentrations of
gallic acid or lactic acid may be required.
The determination of conductivity for boiler water is made by following
the General Operating Procedure given on page 4. To convert the
conductivity reading to parts per million Total Dissolved Solids (ppm
TDS), multiply the reading by 0.7.
EX AM PLE:
Conductivity reading is 3500 micromhos/cm
3500 x 0.7 = 2450 ppm TDS
5