Marine Salinity Tester - Hanna Instruments

The Hanna HI98319 measures electrical conductivity and converts that value to salinity, giving you a fast, repeatable digital result rather than the approximations typical of a plastic swing-arm hydrometer or a manual refractometer. Salinity is reported in parts per thousand (ppt), Practical Salinity Units (PSU), or specific gravity (S.G.), so the readout matches whatever reference you prefer to work with. Temperature is measured and displayed simultaneously on the multilevel LCD, removing any need for a separate thermometer during testing.

An onscreen stability indicator takes the guesswork out of knowing when the sensor has equilibrated with the sample — the display signals when the reading has stopped drifting, which matters when moving between tanks or between water batches of different temperatures. A selectable auto-off function prevents battery drain if the meter is set down and forgotten, extending the usable life of the included CR2032 lithium battery. Hanna rates that battery for up to 100 hours of continuous use, and a low-battery icon blinks as a heads-up before the cell is fully depleted.

The pocket-sized form factor makes the HI98319 practical for water changes, coral propagation facilities, fish-only systems, and field collection work alike. Dual-button operation is intentionally minimal — there is no deep menu structure to navigate during a routine test. The kit includes the necessary calibration solutions and a battery, so no additional purchases are required before first use.

For reef and marine fish systems where stable salinity is critical, a calibrated digital meter like the HI98319 is a meaningful step up from analog tools. Calibrate the unit with the included solutions before first use and periodically thereafter to maintain accuracy. The compact design stores easily near the sump or in a testing kit without taking up bench space.