Applications with ultra-pure water, i.e. water without solids, which has no or only a slight conductivity, as well as applications with water and water-based media to which a maximum of 10% of additives are added, can be solved with the SU Puresonic. If the mixing ratio exceeds the specifications, the sensor will continue to measure, but this the absolute accuracy of the sensor will be compromised. Nevertheless, reproducibility will not be affected.