True Natural Salinity Refractometer "Reef Sea Meter" for Reef Aquarium, Marine Seawater, Hydrometer

THE REEF SEA METER   NATURAL SEA WATER REFRACTOMETER   Specifically designed for aquarium use for measuring the salinity of Natural Sea Water (NSW)   Specifications:     Range:                                                       Minimum Division:                              Accuracy:                          Light Source:   0-40 Parts per Thousand of Salinity in NSW               1.00 PPT                        +/- 1.00 PPT               Ambient: Sunlight or Lamp     1.015 to 1.030 Specific Gravity                                      0.001 SG                        +/- 0.001 SG   Almost all hand held salt water refractometers available to the hobby are designed and calibrated for the testing of brine solutions, i.e. sodium chloride, and are not calibrated for the refractive index of Natural Sea Water.  This is a very important distinction.  Other Salinity Refractometers used for marine aquariums are designed to test salt in water – nothing else!  The Reef Sea Meter is desig