Harveys DualFlo Water Softener Easy to store, handle and load. Non-electric: Cheaper to run than electric machines, no Part P requirement for an electrical outlet near the softener, no complicated timers/ programmers to set up. Quiet in operation. 50 Litres per Min Flow Rate: Suitable for vented or unvented systems and up to a maximum of 2 bathrooms. Twin Tank: Never run out of softened water. Up to 50% less salt usage. Block Salt: Easy to store, handle and load. Compact Size: Fits in a kitchen cupboard. Displacement Metering: Only regenerates upon actual usage.