Water softeners

Hard water leaves scale on water heater elements, in geyser heat exchangers and in washing machines. Protecting appliances does not always need a full softening plant — a compact unit on the line to the appliance is often enough:

• polyphosphate dosing filters — a bowl of crystals that slowly dissolve and stop hardness salts from settling as the water heats; the crystals are topped up as they are used;
• boiler kits — a filter and a dosing unit assembled together for the cold supply before a water heater;
• washing machine models — small dosing units fitted directly on the appliance supply.

If the water is very hard and scale appears everywhere, you need a proper softening system — see how to choose one from a water test in “How to choose a water filter”.