very small amount of water:
Due to the small amount of water there is a very high concentration of dirt in the water. When 3 people go into the whirlpool, the load is the same as when 150 people go into an 8 x 4 m swimming pool.

very high water temperature:
A Jacuzzi is operated with 35 to 38 °C warm water. This is the optimal temperature for bacteria. One bacterium can become 1 billion bacteria in 10 hours at these temperatures.

a strong turbulence of the water:
Due to the strong turbulence of the water, the carbon dioxide in the water is outgassed and this can lead to lime precipitation. The turbulence also causes many disinfectants (such as chlorine) to decompose more quickly.

very high number of pipelines:
A jacuzzi with 50 nozzles can have up to 100 m of piping with 150 sqm of internal surface area. Limestone, fats, cosmetics, bacteria with biofilm can settle there. Many pipelines, e.g. the air lines, cannot be flushed.

very small filter systems in the whirlpool:
Compared to the pollution of the water, the filter systems are undersized and the filter running times are often much too short. As a result, the dirt remains in the spa and must be chemically cleaned.

• Lime and carbon dioxide are always in the water
• They are chemically bonded and dissolved in water.
• A lot of carbon dioxide + a lot of lime in the water = hard water
• Due to the heating and turbulence of the water, carbon dioxide is released and the dissolved lime is transformed into limestone: Limestone is deposited in the inner walls of the pipes. A whirlpool with 50 nozzles has approx. 100 m of piping with an inner surface of approx. 150 m². They can be completely covered with limestone. This keeps bacteria in place and fats settle. The bacteria multiply and form a biofilm.