Designed for Simple Aquarium Salinity Testing Hanna Instruments HI98319 Marine Salinity Tester measures electrical conductivity (EC) to determine the salinity of natural and artificial seawater. Within seconds, the salinity and temperature are measured, and then using the temperature reading, automatically compensated and displayed on the easy to read LCD screen. Ensuring the proper salinity in your reef tank allows your fish and corals more time to grow instead of having to adjust to constant salinity changes. If you have a hard time seeing the fuzzy blue line common with traditional refractometers, or just want to make your life easier, pick up a Hanna HI98319 Salinity Testing Pen!   Easily cycle between the three common salinity measurements: ppt – parts per thousand PSU – practical salinity units S.G. – specific gravity   Range 0.0 to 70.0 ppt (g/L) 0.0 to 70.0 PSU 1.000 to 1.041 S.G. Resolution 0.1 ppt (g/L) 0.1 PSU 0.001 Accuracy (@25ºC/77ºF) ±1 ppt for 0.0 to 40.0 ppt (±2 ppt for readings over 40.0 ppt) ±1 PSU for 0.0 to 40.0 PSU (±2 PSU for readings over 40.0 PSU) ±0.001 S.G.   Temperature Range – 0.0 to 50.0°C (32.0 to 122.0°F) Temperature Resolution – 0.1°C (0.1°F) Temperature Accuracy (@ 25°C/77°F) – ±0.5°C; 1°F SalinityCalibration – Automatic single point 35.00 ppt Temperature Compensation – Automatic from 5 to 50.0 ºC Battery Life – Approximately 100 hours of continuous use Environment – 0 to 50 °C (32 °C to 122 °F) RH max 100%   What’s Included? 1x HI98319 Marine Salinity Tester 1x CR2032 Battery (installed) 1x Storage Case 4x 35ppt Calibration Standard Sachets 1x Instruction Manual 1x Quality Certificate