The In-Situ Aqua TROLL 400 is a compact multi parameter water quality sonde ideal for surface and ground water monitoring applications. You can measure up to water quality 12 parameters using the Aqua TROLL 400. These include: conductivity, salinity, total dissolved solids, resistivity, density, dissolved oxygen, pH, ORP, temperature, water level and pressure.  These parameters are monitored on 6 easy to configure sensors, saving calibration times and costs.  The Aqua TROLL 400 also features Modbus/RS485 and SDI-12 outputs for easy configuration with instruments such as the In-Situ con TROLL pro, and In-Situ Rugged Reader.