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 D: Temperature Effect
Conductivity measurements are temperature
dependent, if the temperature increases, conductivity
increases. eg: the conductivity measured in a 0.01
0
M KCl solution at 20 C is 1.273 mS/cm, whereas, at
0
25 C, it is 1.409 mS/cm.
The concept of reference temperature (Normalization
temperature) was introduced to allow the comparison
of conductivity results obtained at different temperature.
0
0
The reference temperature is usually 20 C or 25 C.
The conductivity meter measures the actual COND.
and temperature and then converts it to the reference
temperature using a temperature correction function
and displays the conductivity at the reference temp..
It is mandatory to always associate the temperature
together with a conductivity result. If no temperature
correction is applied, the conductivity is the value
taken at measurement temperature. The 830x meter
used linear temperature correction.
Linear temperature correction:
In moderately and highly conductive solutions,
temperature correction can be based on a linear
equation involving a temperature coefficient ( ). The
coefficient is usually expressed as a conductivity
0
variation in %/ C.
Linear temperature correction is used, e.g. for saline
, acids and leaching solutions.
K
Tref
=
T-T
ref
K
T
100
100+
( )
25