Conductivity

Salinity and conductivity sensors are among the most widely used instruments in environmental monitoring, oceanography, aquaculture, industrial process control, and water quality management. Though the two measurements — salinity and conductivity — are distinct concepts, they are deeply interrelated. In practice, salinity is almost always derived from a conductivity measurement rather than measured directly. Understanding how these sensors work requires a look at the underlying physics of electrical conduction in water, the engineering of the sensor itself, and the mathematics that ties conductivity to salinity.