Salinity

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.

If you work with water systems — whether in aquaculture, hydroponics, greenhouses, environmental monitoring, or marine research — you’ve probably seen both conductivity and salinity used in dashboards and sensor specs.

They’re closely related.
They are often displayed side-by-side.
But they are not the same thing.

Understanding the difference helps you choose the right sensor, interpret your data correctly, and avoid costly mistakes.