Water Quality


HL4 Multi-Parameter Sonde

Know the instrument is working correctly and troubleshoot quickly. Streamline calibration tasks and produce valid, scientifically defensible conclusions.

Use with the Hydrolab Surveyor HL for attended monitoring, or for unattended continuous monitoring applications, the HL4 has on-board data logging and dedicated communications modules for easy integration with external loggers and telemetry.

Product type: Attended, Unattended
Parameters measured: Temperature, Conductivity, pH/ORP, Dissolved Oxygen (LDO), Turbidity (Self Cleaning), Depth, Chlorophyll a, Blue-green algae, Rhodamine
Product highlights: The next generation multiparameter water quality instrument
Interface: SDI-12, RS-485, RS-232, TTY, USB

  • Self-monitoring system reports the status of the instrument, flags the data, and shows the user where the problem is with assistance on how to solve the issue
  • User-scheduled calibration and maintenance intervals indicate when they are due
  • Guided and semi-automated calibration routines lead the user through the calibration process
  • Calibration results are stored with date and time, calibration type, user identification, and user notes
  • Check Calibration process allows the user to verify calibration and store the results
  • Calibration reports contain information about previous calibrations and calibration checks
  • Sensor status is saved with every line of data and is contained in the log file
  • Dedicated communications modules allow easy integration with data loggers and telemetry systems
  • Compatible with the Surveyor HL – a fully IP67 handheld designed for field use with a full-color screen that is visible in direct sunlight

Sensors Temperature sensor and up to four additional sensors plus depth and ORP
External 6 … 30 VDC (12 VDC nominal) applied to the communications module,12 VDC: 250 mW average, 19 W peak
Internal (Optional) Internal alkaline D-cell battery, non-rechargeable.
Sleep mode at 12 V 20 mA
Communications Hydrolab communications modules: USB, SDI-12, RS232, RS485, or TTY
Memory 4 GB of internal memory; 1 second interval minimum
User Interface
PC Software Hydrolab Operating Software
Handheld (Optional) Hydrolab Surveyor HL
Sonde Depth Rating 200 m (656 ft)
Maximum Deployment Cable 200 m (656 ft)
Diameter w/o bumpers 4.4 cm (1.75 in.)
Diameter with bumbers 5.3 cm (2.1 in.)
Weight with internal battery pack (IBP) and storage/calibration cup 2.2 kg (5 lb)
Length – no IBP, standard sensor guard 51.4 cm (20.25 in.)
Length – no IBP, extended sensor guard 66.4 cm (26.125 in.)
Length – IBP and standard sensor guard 62.2cm (24.5 in.)
Length – IBP and extended sensor guard 77.8 cm (30.625 in.)
Environmental conditions
Operating temperature -5 … 50 °C (23 … 122 °F), non-freezing
Storage temperature 1 … 50 °C (34 … 122 °F)
  • HL4
  • Water Quality Monitoring with OTT HydroMet
  • Hydrolab HL4 Webinar (2014)

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