The Seametrics CT2X is a microprocessor-based submersible conductivity and temperature sensor with built-in data logging. It measures and stores up to 349,000 records of conductivity, temperature, salinity, and total dissolved solids (TDS). An optional depth/level sensor adds pressure measurement in the same compact housing.

The sensor incorporates 4-pole electrode cell technology for conductivity, salinity, and TDS. This design reduces fringe field interference errors, minimizes inaccuracies from polarization effects, and lowers contact resistance problems. The epoxy/graphite conductivity element is extremely durable for rugged field conditions and can be easily cleaned with a small brush. Four-pole technology allows one electrode to cover a wide range from 10 to 300,000 µS/cm with accuracy of ±0.5% of measured value (0-100,000 µS/cm).

The temperature sensor uses a borosilicate glass encapsulated thermistor with ±0.25°C accuracy over -5 to 40°C. Optional pressure measurement employs a piezo-electric, media-isolated element with proprietary temperature compensation. Both linear and nLFn (non-linear) temperature compensation options are available for conductivity readings.

The CT2X supports Modbus RTU (RS485) and SDI-12 v1.3 communication protocols, allowing direct integration with existing telemetry systems. It is powered internally by two replaceable AA lithium batteries (12-month typical life at 15-minute polling intervals) or externally by 9-16 VDC for data-intensive applications. Multiple CT2X sensors can be networked together on a single bus with up to 32 addresses.

Seametrics' free Aqua4Plus 2.0 software provides real-time monitoring, flexible programming, and data export to spreadsheets or databases. The sensor features a narrow 0.75-inch diameter and lengths from 12.5 to 16 inches depending on configuration. Housing materials include acetal, 316 stainless steel, fluoropolymer, and PTFE with titanium optional. Cable choices include polyurethane, polyethylene, and FEP Teflon. IP68 and NEMA 6P rated for continuous submersion.

Applications include wetland surveys, saltwater intrusion monitoring, agricultural runoff studies, discharge monitoring, and general water quality assessment.