Handheld Refractometer

The Handheld Refractometer uses the refractive index of light passing through a water sample to determine salinity and specific gravity. It is the most widely used salinity measurement tool in marine aquariums due to its lack of moving parts, zero power requirement, and portability.

The dual-scale reticle displays both specific gravity (1.000–1.070) and salinity in ppt (0–100) simultaneously, with ATC correction applied across 10–30°C ambient temperatures. A 2–3 drop sample placed on the prism is sufficient for a reading; the measurement takes under 10 seconds once the instrument is calibrated.

Calibration with deionised water or a certified zero-point solution ensures accuracy. Annual re-calibration of the ATC mechanism may be required in heavily used instruments. The compact body fits in a pocket and includes a protective carry case.