Sper Scientific 850038 Pure Water Meter - Manual (Page 43)

Appendix B: Conductivity to TDS
Conversion Factors
Conductivity
at 25 C TDS KCl
ppm value Factor
TDS NaCl
Factor
TDS 442
Factor
23 S 11.6 0.5043 10.7 0.4652 14.74 0.6409
84 S 40.38 0.4807 38.04 0.4529 50.5 0.6012
447 S 225.6 0.5047 215.5 0.4822 300 0.6712
1413 S 744.7 0.527 702.1 0.4969 1000 0.7078
1500 S 757.1 0.5047 737.1 0.4914 1050 0.7
2070 S 1045 0.5048 1041 0.5029 1500 0.7246
2764 S 1382 0.5 1414.8 0.5119 2062.7 0.7463
8974 S 5101 0.5685 4487 0.5 7608 0.8478
12,880 S 7447 0.5782 7230 0.5613 11,367 0.8825
15,000 S 8759 0.5839 8532 0.5688 13,455 0.897
80mS 52,168 0.6521 48,384 0.6048 79,688 0.9961
ppm value ppm value
442: 40% sodium sulfate, 40% sodium
bicarbonate and 20% sodium chloride.
The meter can be calibrated by using TDS calibration
standard solutions. The calibration standard requires
the TDS value at a standard temperature such as
25 C. To determine the Conductivity-to-TDS
conversion factor, please use the following formula:
Factor = Actual TDS : Actual Conductivity @ 25C
Definitions:
Actual TDS: Value from the solution bottle label or
from a standard buffer which made by using high
purity water and precisely weighed salts.
Actual Conductivity: Value measured using a properly
calibrated Conductivity/TDS/Temperature meter.
Both the actual TDS and the actual conductivity
values must be in the same magnitude of units. For
example, if the TDS value is ppm, the conductivity
value must be in uS; if the TDS value is in ppt, the
conductivity value must be in mS.
Check this number by multiplying the conductivity
reading by the factor in the above formula and the
result is the TDS in ppm.
Appendix C: Calculating TDS
conversion factors
41