The WSI3 probe has been developed for the monitoring of water-bearing stratums, rivers, basins, rubbish dumps or however clear or semi-clear waters. The probe is capable of detecting up to 3 different types of ions, and is suitable for applications in freshwater and seawater (excluding Ammonium and Nitrate due to interferences). It is 'possible to choose, depending on application, from: Ammonium NH4+, Chlorides Cl-, Nitrate NO3-, and comes complete with self shielded cable L=30m. It permits simultaneously to carry out a comparative analysis of various parameters, concurring to the reading in real time, the local memorization, or the file transfer to a center of data storage, through the NESA dataloggers mod. TMF100 or TMF500, via GSM, GPRS, UMTS, or via satellite. The probe can be directly interfaced to a PC via USB through the web application "Sonda-Web" that allows to use the probe in monitoring campaigns in the field without the need to have a complete system for acquisition.