Refractometer for seawater and marine fishkeeping aquarium 0-100 ppt Details : This optical refractometer (salinity meter) has scales in the range of 0 - 100 ppt(0 - 10 %). The reading resolution is 1 ppt. It is designed for the measurement of seawater (marine aquaria) or very low concentrated salt solutions. The second scale is for reading of the salt solution density in range 1.000 to 1.070 g/cm3 (resolution 0.001 g/cm3). The usual salinity of the selected aqueous solutions 1.Fresh water --- 2.Brackish water---0.5 to 30 ppt 3.Saline water (Seawater)---30 to 50 ppt 4.Brine--- 50 ppt (Salinity 36 ppt means, that there are 36 grams of salt in 1 liter aqueous solution.) Measurement: The liquid measurement is very easy. Place a few drops of the liquid on the optical part of the refractometer, cover the prism (the liquid will spread more easily over the prism), look throught the eyepiece against the light (focus, if necessary) and you will be able to read the result value on the scale. General technical parameters reference temperature 20 CelsiusATC - automatic temperature compensation (compensation range 0 ~ 30 Celsius) focus possibility length ~ 195 mm quality technical design Content and equipment a firm plastic case a refractometer a cleaning cloth 3 suction tube a screw driver a operating instructions