salinity calibration question

[kac0143]

I calibrated my American marine salinity probe to the apex calibration is 53,000 us. When I go to calibration charts it shows conductivity in ms/cm. Are these the same us and ms/cm? Thanks

 

[Stigigemla]

Conductivity is the opposite of electrial resistance. If you have 2 plates of 1cm x 1cm on a distance of 1cm and measure 1 ohm resistance with an alternating current You have a conductivity of 1S/cm. Millisiemens is the opposite of kilo ohm and mikrosiemens is the opposite of mega ohm.
But the surface and distance between the plates can be different in different methods. A long time ago we used only 1 cm method but now it is (or should be) standardized to 1 m. (1m square plates in a distance of 1 m) 10 us/cm is equivalent to 1 ms/m.

 

[Garf]

53000 microsiemens is 53 millisiemens.

 

[kac0143]

Thanks

 

[Randy Holmes-Farley Verified Community Expert]

Just to be clear, the units are milliSiemens per centimeter (mS/cm), or microSiemens per centimeter (uS/cm). As noted, 1 mS/cm = 1,000 uS/cm.

 

[Stigigemla]

I have had a meter that showed the result in ms/m. It dint stand a saltwater bath.
A quote from wikipedia: "The SI unit of conductivity is S/m and, unless otherwise qualified, it refers to 25 °C. More generally encountered is the traditional unit of μS/cm"

The small handheld meters we normally use are uS/cm

 

[Randy Holmes-Farley Verified Community Expert]

I have had a meter that showed the result in ms/m. It dint stand a saltwater bath.
A quote from wikipedia: "The SI unit of conductivity is S/m and, unless otherwise qualified, it refers to 25 °C. More generally encountered is the traditional unit of μS/cm"

The small handheld meters we normally use are uS/cm

Thanks. Yes, the fact that some numbers in the literature and some meters use slightly different using (such as S/m, not mS/cm) is why I wanted to make it clear that the units quoted above are per cm.