Water hardness and pH are two very important parameters for successful water care in the whirlpool.
Why is this so?
A whirlpool with 50 jets has approx. 100 m of pipes with an inner surface of approx. 150 sqm. In case of lime failure, hard rough limestone can settle on the 150 sqm. Bacteria use limestone as food. Fats and oils that get into the water through the skin easily stick to the rough surface and additionally serve the bacteria as nutrients.
If several bacteria can settle down and get enough nutrients, they start with an accelerated cell division (reproduction). At 37° water temperature bacteria can double their number every 20 minutes. One bacterium can become 1 billion bacteria in 10 hours.
As soon as several bacteria group together, they start to produce a kind of mucus called biofilm. This biofilm has many functions. The main function is to protect the bacteria from disinfectants. Another function is to filter nutrients from the water and to provide the bacteria with it. Biofilms in the pipes should be avoided at all costs. Therefore, it is very important to control the water hardness and the pH-value.
What is the relationship between water hardness and pH value?
When it rains, rainwater accumulates with the gas carbon dioxide from the air. Carbon dioxide is acidic and so the rainwater becomes slightly acidic. It has a pH value below 7.0.
If the rain falls to the earth and seeps through a layer containing marble, for example, the acidic water dissolves limestone and absorbs dissolved calcium ions. These calcium ions are in a chemical equilibrium with the acidic water.
Water with a lot of dissolved calcium ions is called hard water. There are different units with which one can indicate the water hardness. We use the unit "degree of German hardness".
- From 7 - 10 °dH is perfect water for whirlpools
- From 1 - 10 °dH is soft water
- From 10 - 13 °dH is medium hard water
- At 14 °dH water is considered hard
The conversion into °fH (degrees of French hardness) = 1 °dh x 1,78
The conversion into °eH (degrees of English hardness) = 1 °dh x 1,24
You can ask your water supplier for the water hardness of your water or measure it with our total hardness test kit.