Yes we do. One is for freshwater conductivity measurements and the other is for saltwater (marine) conductivity measurements.
We can incorporate two different types of conductivity sensors on to our XR(X) series loggers. The inductive cell sensor is suitable for marine, brackish and freshwater applications whereas the electrode sensor is only suited to freshwater where the conductivity is less than 2 mS/cm. (Please contact us if your application is in low ionic water). The inductive sensor is accurate across the full salinity range specified by PSS78, though it can also be used in high salinity brine seen in desalination plants etc.
The freshwater conductivity sensor is generally only selected for very low conductivity value measurements as it has an very low electrical noise level; 0.01 µS/cm (rms) compared to a very respectable level of 0.5 µS/cm (rms) for the inductive sensor.
There is about a less than 20% price premium for the freshwater logger over the marine logger.
If you are working in Arctic lakes with high water purity and you want the detailed fine structure of the water conductivity, it is worth paying the extra for the freshwater cell. If on the other hand, you want an extremely rugged sensor that is capable of operating in all conditions and can recover from being frozen and withstand cleaning of contaminants or biofouling, then you should select the inductive sensor.
The sensors are indicated by a lower case m (marine) or f (freshwater) in the instrument part number."
