Refraktometr ATC used for salinity measuring
A refractometer is considered by many to be a more accurate way to measure salinity. It has no floating parts like hydrometers. The big feature is that a refractometer can be calibrated to ensure accuracy. Unlike hydrometers, refractometers have automatic temperature compensation (ATC) so you don’t have to worry about your tank’s water temperature when taking a measurement. Many aquarists have made the switch to a refractometer to make mixing up batches of saltwater easier too.