This allows you to proactively initiate water care measures, avoid pungent indoor pool smells and at the same time reduce operating costs and protect the environment by dosing chemicals as required and using energy-efficient partial load operation in accordance with DIN 19643-1. The new sampling station can be seen from October 22 to 24, 2024 at Interbad 2024, the international trade fair for swimming pools, saunas and spas in Stuttgart (booth IJ41).
So-called chloramines are the problem child of many swimming pool operators. The chemical compounds are always formed when free chlorine in the water reacts with organic substances such as urea from urine and sweat after the disinfection process. "Even at low concentrations, chloramines cause a pungent smell that has scared off many a swimmer. For people with weakened immune systems, they can even cause a health hazard," says Thomas Beutel, an expert in swimming pool technology and dosing systems engineering at Lutz-Jesco GmbH. The standardised specifications therefore set strict upper limits for bound chlorine - in Germany, for example, 0.2 mg/l. "In order to reliably and accurately determine the concentration of bound chlorine in the water, we have developed a new type of sampling station which we will be presenting for the first time at Interbad 2024." Future users include large spas and attractive hotel pools.
New measuring cells enable reliable determination of bound chlorine
The solution for determining the bound chlorine works as follows: Water samples from the swimming pool flow continuously through the sampling station. Integrated sensors record the various water parameters such as free chlorine, total chlorine, redox voltage and pH value. The station then calculates the amount of bound chlorine based on the difference between total chlorine and free chlorine. This method is necessary because bound chlorine comprises a large number of different compounds with different chemical properties, which would be too time-consuming to measure individually.
However, this differential calculation has been the Achilles heel of many measuring systems to date, as the determination of chlorine values requires constant readjustment and often additional manual tests and is nevertheless often prone to errors and inaccurate,’ says Beutel. ‘To solve this problem, we have focussed on special membrane-covered and ion-selective measuring cells for free chlorine and total chlorine in the new sampling station, which are perfectly matched to each other. This enables an exact and fast differential calculation.’ Operators can read the exact value of the bound chlorine and other water parameters at a glance on the device's display - without the need for constant adjustments and time-consuming manual measurements.
Sampling station enables automated and professional water care
Thanks to the determination of unbound chlorine, proactive and automated water care is possible. Users can connect various actuators such as dosing pumps to the sampling station and have them controlled by a multi-channel controller that processes the signals from the sensors. ‘The system can then add more chlorine to the water outside of operating hours, for example, in order to eliminate the increasing amount of chloramines through so-called breakpoint chlorination,’ says Beutel and explains why the investment in the new sampling station can quickly pay for itself. ‘With the new technology, it is possible to reliably keep the values for bound chlorine below 0.2 mg/litre. This enables swimming pool operators to avoid unpleasant indoor pool smells and optionally realise reduced partial load operation in accordance with DIN 19643-1, thereby saving energy costs. In addition, the precise and reliable measured values ensure that chlorine is dosed economically and as needed, and that further controlled process steps are carried out to reduce chlorine levels, such as the use of powdered activated carbon. With energy costs becoming increasingly expensive, the investment can therefore pay for itself within just a few months.’
