Refractometers

Using refractometers, you need to know that the refractive index is a function of temperature, and you can wind up with non trivial errors in derived salinity if the temperature of the sample isn't what it should be. Refractometers are instruments that measure the bending of light as it crosses an interface between dissimilar substances. Digital refractometers and other refractometer equipment are now available to order from the resources found here. A refractometer is the only accurate way to test the concentration of a substance in a liquid.