Instruction Manual
PC 300
59
14 ADDENDUM 2: CALCULAT ING TDS CONVERSION
FACTORS
You can calibrate your meter using TDS calibration standard solutions. The calibration
standard only needs to give the TDS value at a standard temperature such as 25 °C. To
determine the conductivity-to-TDS conversion factor use the following formula:
Factor = Actual TDS ÷ Actual Conductivity @ 25 °C
Definitions:
•
Actual TDS: Value from the solution bottle label or as a standard you
make using high purity water and precisely weighed salts.
•
Actual Conductivity: Value measured using a properly calibrated
Conductivity/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 in ppm the conductivity value must be in µS; if the TDS
value is in ppt the conductivity value must be in mS.
Check your factor by multiplying the conductivity reading by the factor in the above formula.
The result should be in TDS value.
