Collection: Hydrometers & Refractometers

Salinity Is the One You Can't Guess

Every other parameter drifts slowly. Salinity moves every time water evaporates, and livestock feel it fast. Getting it right depends less on which tool you buy than on using it properly — and on knowing what each one can and can't do.

Swing-Arm, Glass or Optical

• Swing-arm hydrometers — inexpensive and quick. Rinse and dry between uses; trapped bubbles and salt creep are the usual cause of a bad reading.
• Glass floating hydrometers — a laboratory-style float read at a stated reference temperature, giving a stable result when used at the right temperature.
• Optical refractometers — a few drops on the prism gives a direct reading, and they can be recalibrated as they drift.
• Calibration solution — a known seawater standard, so you can check a refractometer rather than trust it.

Whichever you use, take readings at a consistent temperature and check the tool against a standard now and then. Questions? Email info@jlaquatics.com.