Main features of Red Sea’s Seawater Refractometer include: •Directly reads the absolute salinity of seawater at 25°C/77 0F (No need for seawater or temperature compensation factors) •Specifically designed for the ionic content of seawater (NSW) for more accurate salinity measurement (industry standard refractometers are calibrated for salt brine). •Calibrated for seawater (NSW) at 25oC/77oF, the normal temperature range for reef aquariums (most standard refractometers are calibrated at 15oC/59oF ). •Easier to read, higher resolution display, focussed to the relevant range for reef aquariums from 0 to 40ppt - other refractometers compress a range of 0 to 100ppt in the display forcing the lines to be much closer together and harder to read •Includes Integrated Automatic Temperature Compensation (ATC) for accurate measurement at standard ambient temperature.
Salinity is a general term describing the concentration of salt in water. However, solutions of different type of salts have different refractive indexes. Brine is a solution of Sodium Chloride (table salt) that contains 2 chemical elements. Seawater contains approximately 70 chemical elements that include Calcium, Magnesium, Potassium etc. in addition to the Sodium Chloride. Seawater and Brine of the same salinity (i.e. the same weight of salt/liter) have different refractive indexes and will give different salinity readings if measured on the same refractometer. Refraction & refractive index All transparent materials such as liquids refract (distort) light. All transparent materials refract light differently and have what is called a “refractive index” which means how much a particular material distorts light. Different concentrations of the same liquid have different refractive indexes. The scale of a refractometer is calculated by using a mathematical algorithm that relates the measured refraction to its concentration for a specific liquid.
Here's what Reef Builders said about the Red Sea Refractometer. "The first thing that caught our eye was the crisp blue and white division on the scale and the larger numbers making it easier to read"
