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Guildline’s Autosal 8400B Laboratory Salinometer is the recognised industry standard instrument for measuring salinity in the laboratory. The Autosal employs a unique continuous flow system, where the sample water is drawn under low air pressure from the original sample bottle.

A high stability temperature control bath and heat exchanger maintain this sample at a precisely defined temperature during analysis, avoiding the need for temperature compensation. The accuracy is better than 0.002 Equivalent Practical Salinity Units (PSU) and has been achieved by improvements in the temperature stability of the bath.

The unique continuous sample flow system offers a marked improvement in speed and convenience over the conventional salinometer method requiring several discrete sample volumes for flushing and measurement. Only 50 mm of sample water are required to achieve a final reading, including flushing and semi-automatic operation gives the final digital readout of conductivity ratio in less than one minute.

The 8400B has a redesigned sample bottle holder, providing easy attachment for original sample bottles. There is a bottle data logging facility built in as standard, which provides output of conductivity ratio, bottle number, bath temperature and standardization reference number.

Bath temperature is selectable from 18°C to 33°C in 3°C steps and there is a window for viewing sample water under test flowing through the conductivity cell. Operating controls include conductivity range select, display function switch for zero, standby or read, bath temperature control check, standard seawater standardization set, temperature bath drain and fill controls, and a sample flow rate control which permits deep cold water samples to be measured immediately.

Particular care has been taken to improve the power supply to the 8400B in comparison to earlier Guildline salinometers, with better input filtering and a new cable harness. There is a heater failure lamp included on the front panel and a front sub-panel reduces wear on the internal hoses when the front door is opened for maintenance. There are also significant changes internally to improve ease of maintenance, such as access to the pumps.

Annual servicing of salinometers is highly recommended to maintain the high accuracy of the units, with a full electronic alignment undertaken every 2 years. Please contact us to arrange servicing.


Initial Setup video guide

Standardisation & Sample Run video guide


Data Sheet

Application Notes


  • Accuracy < ± 0.002 Salinity
  • Range 0.004 to 76 mS/cm
  • Improved temperature stability
  • No temperature compensation required
  • Small samples & rapid measurements
  • Data logging standard
  • Improved maintainability

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