Red Sea Seawater Refractometer (R12018)

Product no.: 114753

The Red Sea Refractometer has a scale adapted to the reef aquarium hobby.

This will help you find your way around faster and measure more reliably.


Maintaining a correct and stable salt content is an essential part of successful care of corals and fish in marine aquariums.

The recommended dosage of our salt mixture and the Reef Care care program varies according to the salt content.

Salinity is a general term that describes the concentration of salt in a water solution.

The different types of salts also have different refractive indices. A saline solution of sodium chloride consists of 2 chemical elements.

Seawater, on the other hand, consists of about 70 chemical elements, such as calcium, magnesium, potassium, etc., which are contained in addition to sodium chloride. Therefore, seawater and saline solution with the same salt content (i.e. the same weight of salt/litre) have different refractive indices and give different salinity values when measured on the same refractometer.

Absolute salinity of seawater The Promilles scale (PPT) of the Red Sea Sea Seawater Refractometer is calculated by an algorithm based on seawater and thus the absolute salinity of seawater is obtained when reading.

The promilles scale (PPT) of conventional salinity refractometers are calculated based on an algorithm of table salt. The use of a salt refractometer in seawater can result in deviations of around 1.5pp of the salinity value.

ATC - Automatic Temperature Compensation

Temperature is probably the most common cause of incorrect readings with a refractometer.

Calibration and testing of water samples is essential before the refractometer and water sample are adjusted to the correct temperature. Automatic Temperature Compensation (ATC) compensates for a few degrees difference between the ambient temperature and the calibrated temperature of the refractometer. Larger temperature fluctuations will lead to an approximate deviation of about 1.0ppt in the reading of the salt content. ATC cannot adjust the PPT scale of the refractometer to the temperature of the aquarium!