Specifically designed for aquarium use for measuring the salinity of Natural Sea Water. Almost all hand held salt water refractometers available to the hobby are designed and calibrated for testing of brine solution, i.e. sodium c...
The Captive Purity Refractometer is an incredibly accurate and easy to use device that eliminates the confusion associated with inexpensive hydrometers. Just place a couple of drops of water on the prism and hold to the light. Rea...