A precision handheld optical refractometer for measuring salinity and specific gravity in marine aquariums, reef tanks, and aquaculture systems. With Automatic Temperature Compensation (ATC) and dual-scale reading, this is an accurate and reliable tool for any serious marine keeper. Salinity is one of the most important parameters in a marine or reef aquarium. Too high or too low and your fish and invertebrates will suffer. A refractometer gives you a fast, accurate reading from just a few drops of water — far more reliable than cheap plastic hydrometers. Key Features: • Dual scale: specific gravity (1.000–1.070) and salinity in parts per thousand (0–100 ppt) • Automatic Temperature Compensation (ATC) — accurate readings between 10°C and 30°C • Requires only 2–3 drops of water for a reading • Optical refractometer — no batteries required • Calibration screw for ongoing accuracy • Includes pipette, calibration fluid, and protective case 📋 How to use: Calibrate with RO water before first use and periodically thereafter for most accurate results. Also useful for testing the output of your RO membrane — pure RO water should read zero salinity.
