Sensor apparatus systems, devices and methods

A cassette manifold comprising a plurality of fluidically separate fluid paths, allowing the fluid paths to carry fluids having different compositions or characteristics, each fluid path including two probes, at least one probe being a thermal well adapted to receive a sensor for transmitting temperature, the two probes permitting conductivity sensing of fluid passing along the fluid path.

A dialysis apparatus comprising a cassette for sensing liquid in the dialysis apparatus, the cassette comprising a housing having a plurality of fluid paths, at least one fluid path includes

• a first probe comprising an electrically conductive well for transmitting temperature of fluid passing along the fluid path, wherein the well is adapted for interconnection with a thermal sensor,
• a second probe comprising an electrically conductive material that together with the first probe permit a conductivity measurement to made of the liquid in the at least one fluid path,
• wherein the conductivity measurement is used to determine the clearance of the dialyzer.