Technology inspired by the sea: how salt water treatment works in swimming pools
7.5.2026
Martin Býšek
While traditional water treatment methods, as discussed in our article on conventional chlorination technology, rely on the external dosing of oxidising agents, a salt water system is based on a different principle. It is not an alternative to chlorine, but an autonomous process that produces chlorine directly within the hydraulic circuit of the filtration technology. This method turns the pool into a closed chemical system, where success depends on the correct input parameters and on material compatibility, which must be designed with the specific physical and chemical properties of the electrolyte in mind.
From Homogenization to Electrolytic Balance
The technical process itself begins by dissolving salt with a purity of over 99% at a ratio of of 3–4 kg per 1 m3 water. This achieves a salinity of approximately 0,3-0,4 %, a level at which the electrolytic cell is able to produce chlorine through the electrolysis of the salt dissolved in the water. Before the electrolysis process itself is started, however, it is essential to let the water circulate for at least 24 hours without activating the cell, so that the solution is fully homogenised.
At this stage, it is also essential to stabilise the total alkalinity within the range of 80–120 ppm and ensure a pH value of 7.2. Without these initial conditions, the subsequent automatic control system would be forced to operate in an unstable environment, leading to inefficient production of active chlorine and the risk of cloudy water.
Material Integrity and Corrosion Protection
A key difference from the chlorination technology described earlier is the effect of salt water on the integrity of metal components. Salt significantly increases the electrical conductivity of the water, which accelerates galvanic corrosion. From a technical perspective, standard stainless steel is therefore unsuitable for use in salt water pools. Highly resistant steel or titanium must be used instead. Protective bonding of all metal parts must also be carried out consistently throughout the system in order to eliminate stray currents. These technical measures are the invisible but absolutely crucial difference between a professionally designed system and the mere installation of a salt chlorinator in a standard pool circuit.
Automation and Precision Salinity Management
Operational maintenance of a salt water system focuses on compensating for sodium hydroxide, a by-product of electrolysis. This naturally and continuously raises the pH level, a process that conventional chlorination systems do not experience to the same extent. An automatic dosing station is therefore an essential part of the technology, monitoring and reducing the pH in real time to prevent calcium deposits from forming on the cell electrodes. When it comes to maintaining salinity, it is important to remember that salt does not evaporate from the water. Its loss is purely mechanical – through being carried out on bathers’ bodies or during filter backwashing.
Salinity can now be monitored digitally and is often integrated directly into the salt chlorinator system. Salt should always be topped up with care to avoid exceeding the conductivity limit for which the given electrolytic unit is designed. When adding salt to the pool, it is important to keep the filtration system running so that the salt dissolves as quickly as possible and does not remain on the bottom or any other part of the pool. If this happens despite our best efforts, the affected area should be stirred up as quickly as possible, for example using a manual pool vacuum or pool net. One suitable approach is to add the salt gradually around the perimeter of the pool.
The Comfort of Soft Water: Excellence by Design
When combined with the right design and technology, salt water offers a technologically elegant solution for those seeking the comfort of soft water with minimal need to handle chemicals in concentrated form. However, it requires a higher level of engineering expertise in the design of the hydraulics and the protection of materials. While conventional chlorination technology places fewer demands on materials and therefore allows stainless steel components to be used in the pool, a salt water system is ideal for those looking for water that is gentler on the skin and has a less pronounced chlorine odour in everyday use.