The real measurements is the conductivity, the real figure you get is x mS (milli Siemens). This should be transformed to a form we can refer to. Since long time ago - there is a standard of seawater salt content in use. If you want to understand the differences please start reading here. Go further here. here, here, here, here and here
But - this is one problem and the one you ask for clarifications of. Your real measurement of the conductivity could be false if you have not done the calibration well enough. The conductivity measurement is very dependent of temperature - therefore it is important that you do the calibration right and in a temperature as close as possible to the standards demand of temperature. A constant measurement of conductivity also demands a rather high flow to the probe because if tiny air bubbles forms on the electrode - the reading will be erratic.
To measure salinity by conductivity its not an easy task. Its easy to do mistake. When i calibrate my probe - I first test with my refractometer - calibrated with a fresh calibration fluid (for refractometers) When I calibrate my conductivity probe - I manipulate the input sample temperature in a way that I get a rather alike PSU reading as i get from my refractometer.
Sincerely Lasse
But - this is one problem and the one you ask for clarifications of. Your real measurement of the conductivity could be false if you have not done the calibration well enough. The conductivity measurement is very dependent of temperature - therefore it is important that you do the calibration right and in a temperature as close as possible to the standards demand of temperature. A constant measurement of conductivity also demands a rather high flow to the probe because if tiny air bubbles forms on the electrode - the reading will be erratic.
To measure salinity by conductivity its not an easy task. Its easy to do mistake. When i calibrate my probe - I first test with my refractometer - calibrated with a fresh calibration fluid (for refractometers) When I calibrate my conductivity probe - I manipulate the input sample temperature in a way that I get a rather alike PSU reading as i get from my refractometer.
Sincerely Lasse