Hydrolab HL4


The Hydrolab HL4 is the next generation multiparameter water quality sonde from OTT Hydromet, provides Streamline calibration tasks and produce valid, scientifically defensible conclusions. Use with the Hydrolab Surveyor HL for attended monitoring, or for unattended continuous monitoring applications.


Attended monitoring, continuous unattended and real-time monitoring.

Salt or brackish water bays, estuaries, and near-coastal areas.

Parameters measured

Temperature, Conductivity, Depth, pH, Dissolved Oxygen (LDO), Turbidity, ORP, Clorophyll a, Blue-green algae, Rhodamine, Ammonium, Nitrate, Chloride.


SDI-12, RS-485, RS-232, TTY, USB