Water filter against limescale - what's the point?

Instead of an ion exchange system, you can also install a limescale filter. What this brings, how exactly the technology behind it works, and where the advantages and disadvantages compared to traditional water softening are, is explained here.

How the limescale filter works

Catalyst technology is used in a limescale filter such as that offered by Biocat.

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The calcium and carbonate ions present in the water usually crystallize only with great difficulty and only where they can. The activation energy required for crystallization is missing in order to combine itself into crystals.

However, pipe walls offer lime crystals a way of depositing themselves. Over time, more and more ions accumulate on these tiny crystals along the pipe walls, and the deposits grow more and more over time.

Limescale filters want the ions to form free crystals. These free crystals can then no longer precipitate and can move freely in the water. This avoids deposits.

In order to stimulate the calcium and carbonate ions to crystallize, specially designed plastic beads are used in the filter. They reduce the activation energy required for crystallization and cause the ions to form tiny crystallization nuclei in the water.

After passing through the filter, these crystallization nuclei lie freely in the water and gradually bind all the dissolved lime into their crystallization structures. Crystals are formed which are later simply washed out with the water and no longer accumulate anywhere.

The plastic beads only serve as a catalyst - they are not used up, but only stimulate the calcium ions to form crystallization nuclei.

Advantages and disadvantages of limescale filters

Limescale filters do not reduce the hardness of the water. They only let the lime contained in the water crystallize into solid structures so that it cannot be deposited anywhere.

The advantage of the method is that it is a filter that requires nothing to be serviced, nothing to be refilled and no energy to be added.

The disadvantage is that the crystals continue to deposit as lime soaps, the taste of the water is not improved and the same amount of detergent is required as before. However, deposits are no longer possible.

Comparison of ion exchange systems

Ion exchange systems, on the other hand, actually remove the lime from the water. However, they mean a high purchase outlay and have to be maintained on an ongoing basis. The salt consumption per month is around 10-15 kg.

Tips & Tricks In any case, it only makes sense to soften the water from a hardness of significantly more than 14 ° dH. Even then, you should consider in advance which devices you actually want to protect or what you want to achieve with the softening.