Basic requirements for healthy bathing and swimming are state-of-the-art water treatment. Both in the interest of health and in order to maintain the value of a facility, water treatment should be performed according to the motto "as much as necessary and as little as possible".

Of course, the treatment result must be checked regularly to determine, particularly under the aspect of changing operating conditions, that the water treatment is optimal in the ideal case. In case of deviations from the recommended values, immediate measures can be taken to exclude a potential health risk from the beginning.

So far - so good. Now, private pools & spas are opening up unexpected alternative possibilities to approach the goal of optimal water quality. However, both in advertising statements and in press releases the terms "chemistry" (science of substances and their compounds, source: Duden) and "alchemy" (chemistry of the Middle Ages; black art, source: Duden) are often blurred. The following explanations, which by no means claim to be complete, but rather a colourful bouquet of statements from various providers, should serve to provide inspiration for thought "with a winking eye".

Let us start with the classic "From now on only salt germination". What is meant by this? The salt electrolysis process! How does it work?

In chlorine electrolysis plants in inline operation the electrolysis cell is undivided. To use this process, a chloride concentration of more than 1200 mg/l in the pool water is required (salt content is equal to 2000 mg/l NaCl). 

Part of the chloride contained in the pool water reacts at the anode to form chlorine. The chlorine produced reacts with the water in the cell to free chlorine.

Caustic soda and hydrogen are produced at the cathode. The caustic soda solution causes an increase in the pH value and the hydrogen produced escapes via the water surface. A sufficient supply of outside air must be provided to ensure that no ignitable mixture can form in the operating rooms and in the swimming pool area.  

To put it in a nutshell - sodium chloride (NaCl), i.e. common salt, is the starting product for the formation of chlorine on site (in situ).

The next product eliminates bacteria fully automatically and without chemicals using UV light. This is all well and good, but only half the truth. Although the water is sterile after treatment, there is no depot effect in the pool or spa. So a disinfectant is still needed in the pool itself, although in lower concentrations if necessary. 

"Have you ever bathed in drinking water?" As usually, yes, for example after the initial filling of the pool with water from the mains. "The ozone generator guarantees this healthy bathing pleasure without chemicals". You should know the following:

Ozone (O3), an active form of oxygen (O2), is a very strong oxidant. Because of its toxicity, it is only used within the treatment section, i.e. after the required contact time is removed from the water to be treated by activated carbon filtration (sorption filtration). A maximum of 0.05 mg/l ozone may be measured at the outlet of the sorption filter in the public bathing area (limit value). Why should it be different in the private bathroom?

"No germs. No bacteria, no algae, no Legionella, no haloforms, no THM, no AOX, no odours, no skin and eye irritation. Pure oxygen". Well, if that is the case, you could easily dispense with the remaining stages of water treatment within the water cycle. 

"Another approach and another principle of effect". The core element of the revitalisation process is water. The active medium in the water revitalisation devices known as "information water" is a water of high order, which is able to transfer a high order even to inanimate water without coming into contact with the information water.

However, the manufacturer points out, in all fairness, that this type of information transfer is not yet measurable with conventional scientific analytical measuring methods.

Finally, a PR article about a plant-based product:

"The patented water care product is specially designed for whirlpools. It disinfects the water completely without chlorine using plant-based ingredients. These reduce the surface tension of the water and prevent the development of a so-called biofilm in which bacteria can multiply. The application is simple: put a cup into the whirlpool once a week, switch on the water jets for two minutes to mix everything - that's it.

In addition, an ozonator should be available for disinfection. Otherwise, chlorine-based cleaning tablets are used in the filter. Furthermore, the water should be changed every three months".

Have you noticed the contradiction? Hopefully this article has made you a bit more aware of this issue and you have an early start to the Pool & Spa season and long, sunny weather with the best water quality.