Fritz 35ppt Refractometer Calibration Fluid is a precision laboratory-standardized solution designed to accurately calibrate optical refractometers, hydrometers, and digital salinity meters for marine aquariums. Unlike pure RO/DI water, which only calibrates at zero, this fluid provides a true 35ppt (1.0264 S.G. at 25°C / 53 mS/cm) benchmark that aligns directly with natural seawater parameter targets, eliminating measurement drift and offset errors. Using pre-measured, ready-to-use calibration fluid ensures your testing equipment delivers trustworthy salinity readings, protecting sensitive reef livestock and delicate stony corals from accidental osmoregulatory stress.
