Captive Purity Refractometer
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. Reads in percent and specific gravity. An absolute must for the serious marine hobbyist.
The Captive Purity Refractometer is an optical device (no batteries) dual scaled 0-100% specific gravity: 1.0 to 1.070. Calibrate with distilled water. Adjustable eyepiece, carrying case, pipette included. This model is ATC (automatic temperature compensating).
User Manual:
Manufacturer Info
Captive Purity manufactures water filtration and water testing supplies for marine and reef aquaria. The brand is best known for their high-quality line of reverse osmosis filter systems and accessories. Captive Purity also produces refractometers for testing salinity, portable pen-sized meters for testing pH as well as replacement filter media for their RO and RO/DI filter systems.
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