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How to adjust residual hardness

A softener will remove all the hardness from the water: a small quantity of untreated water needs to be mixed with the water treated by the softener to obtain the desired residual hardness, between 6 and 12 degrees French. Softeners are generally fitted with a screw to mix the raw water with the treated water, or a bypass for precise adjustment.

What is the correct water hardness?

In a house or apartment, a water hardness of between 6 and 12 °F (French degrees) is considered ideal. Small amounts of magnesium and calcium in your tap water can also be good for your health. However, if you notice that your water leaves traces of limescale on your surfaces or in your appliances, this means that the minerals it contains are reaching saturation point, and that softening would be beneficial for your well-being, the lifespan of your appliances and your energy costs.

What is the French degree?

This is a measure of water hardness. One French degree (°F or TH) corresponds to 10ppm or 10 mg of calcium carbonate per litre of water. 

Can I drink tap water with a water softener?

Yes. The water softener does nothing to alter the drinkability of the water: it acts specifically on its hardness.

Side effects caused by a water softener

As long as the residual hardness of the water is within the prescribed limits, there is no risk of side effects. 

What are the advantages of a water softener?

There are many advantages to installing a water softener:

  • Mineral limescale deposits no longer stick to water heater plates, pipes, bathroom enamel, your skin or clothes. Your skin becomes soft again, laundry no longer comes out rough to the feel, your enamelled items are preserved and the limescale traces do not appear again, which also means you can reduce your use of detergents. You gain in comfort and your appliances can operate at full capacity, with no loss of energy
  • Protection of household appliances that use water.
  • Energy savings (up to 30%) from condensing boilers.
  • Subsequently, pipes freed of limescale blockages allow water to flow more easily, which also saves energy.

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