The USF softener units purify both small volumes and several hundred cubic metres of water per hour. They are controlled by means of central control valves or – for large systems – through PLC and single valve operation. Small systems run in duplex mode, i.e. one softener vessel is in operation and a second is in standby mode. Parallel operation is used for larger systems: both vessels are in operation and are constantly traversed, which is advantageous for critical microbiological applications. The softener units work through volume or quality control by means of online hardness measuring. We use plastics (PVC, PP, PVDF) or stainless steel as pipe materials, and the filter vessels are also optionally available in stainless steel.