13
TDS range
A conductivity measured value can be corrected to a total dissolved solids value using the TDS factor.
Salinity
The salinity is derived from the conductivity of a sample.
Salt % range
The percent of salinity in a sample is dependent on the sample and the salinity coefficient.
For practical reasons, the salinity of a solution is derived from the salinity of the seawater. Two methods
of calculating the salinity from the conductivity are supported:
• Natural seawater scale
• Practical salinity scale
Natural seawater scale (UNESCO 1966)
According to the definition, salinity of a sample in ppt is calculated using the following formula:
R
T
=
C
T
(sample)
C(35;15)·r
T
r
T
=1.0031·10
-9
T
4
–6.9698·10
-7
T
3
+1.104259·10
-4
T
2
+2.00564·10
-2
T+6.766097·10
-1
R=R
T
+10
-5
R
T
(R
T
–1.0)(T–15.0)[96.7-72.0R
T
+37.3R
T
2
–(0.63+0.21R
T
2
)(T–15.0)]
OPERA
TIONAL GUIDE
Resistivity range
The reciprocal of the conductivity of a material is the resistivity.
