10 Best Refractometers for Saltwater Aquariums (September 2026)

Best Refractometers for Saltwater Aquariums

A refractometer is an optical instrument that measures how light bends through a liquid sample to determine its salinity, making it the most accurate tool for maintaining stable water conditions in saltwater aquariums. After losing a $400 coral frag to a sneaky 1.032 salinity spike (caused by a cheap hydrometer that read “fine”), I promised … Read more