Salt chlorination is a method of swimming pool disinfection that uses common salt (sodium chloride) to generate chlorine automatically.
This system keeps the water clean and free of bacteria and algae, without the need to add chlorine directly to the water, as in traditional systems.
Definition and basic operation
In a salt chlorination system, the pool water is mixed with salt in low concentrations, around 6 grams of salt per litre of water.
This saline water then passes through a device called a salt chlorinator, where electrodes generate an electric current that breaks down the salt into sodium and free chlorine (Cl₂). This chlorine is responsible for disinfecting the water and keeping it in optimal conditions for bathing.
Through this process, chlorine is generated constantly and automatically, avoiding the need to dose it manually.
Difference between a salt pool and a natural pool
As a company that works with natural pools, we have found that there is a common confusion between natural pools and salt chlorinated pools.
We are often asked the question: ‘Are salt pools natural pools? And the answer is no.
Salt pools are chlorine pools, as they use a chemical process to generate chlorine from salt, whereas natural pools are purified by plants and without chemicals.
While it is true that the salt chlorination system allows better control over chlorine dosage, it is not a natural process.
How a salt chlorination system works
The salt chlorination system is based on the electrolysis of salt water. This process converts the salt dissolved in the water into chlorine, which is then used to disinfect the pool automatically.
Salt electrolysis process
When salt is added to the pool, the water undergoes a process of electrolysis as it passes through the salt chlorinator. In this process, the electrodes generate an electric current that separates the sodium and chlorine ions.
The sodium remains in the water, while the chlorine is released as a gas, which quickly dissolves in the water, transforming it into free chlorine that oxidises impurities, eliminating bacteria and algae.
How much salt does a salt chlorinated pool need?
Generally, the amount of salt needed is low compared to seawater, with a concentration of about 6 grams of salt per litre of water. Approximately 6 kilos of salt per cubic metre of water.
This ensures that the system works properly and produces the chlorine needed to keep the pool in optimum condition.
Advantages of salt chlorination
The salt chlorination system has several advantages over traditional methods of chlorine disinfection.
Reduced use of chemicals
One of the major benefits of this system is the reduction in the use of chemicals.
By automatically generating chlorine from the salt dissolved in the water, it is not necessary to add large quantities of chlorine in liquid or tablet form, as is the case with traditional pools.
This also reduces the chemical waste often associated with chlorine pools.
Automatic chlorine dosing
In traditional systems, too much chlorine was often added, causing a strong odour and adverse skin or eye reactions.
With salt chlorination, the device doses the chlorine precisely, always maintaining an adequate level of disinfection without excess.
Reduced chlorine odour
With salt chlorination, as there is no excess chlorine in the water, the characteristic and annoying smell of chlorine is reduced, which makes the atmosphere in the pool much more pleasant, in exchange we have water with a salty taste reminiscent of sea water.
Disadvantages of salt chlorination
Despite its advantages, salt chlorination is not without its drawbacks and some challenges to consider in pool maintenance.
pH regulation and use of additional chemicals
One of the most important aspects to consider is the need to control the pH of the water.
The chlorine produced by electrolysis is most effective in a specific pH range, usually around 7.4.
If the pH of the water is not well regulated, the chlorine will not work efficiently.
In our experience, it is always necessary to use acids or bases to adjust the pH, which involves constant maintenance, just as in traditionally chlorinated pools.
Common problems in areas with different water quality
As with natural pools, the quality of the filling water directly affects the performance of the salt chlorination system.
For example, in areas where the water is naturally acidic or contains high levels of phosphorus, problems with algae and other contaminants may occur, despite the use of salt chlorination. Complementary products such as flocculants or algaecides are needed to keep the water clean.
Maintenance of a salt chlorinated pool
The maintenance of a salt chlorinated pool is similar to that of a conventional pool, with some key differences that require attention.
Adjusting the pH in a salt chlorinated pool
As mentioned above, it is vital to keep the pH of the water at a suitable level.
The pH should be checked and adjusted regularly to ensure that the chlorine generated is working properly. This is particularly important in regions where the pH of the water tends to fluctuate due to factors such as water hardness or local chemical composition.
Need for supplementary chemicals
Although salt chlorination generates chlorine automatically, it is still necessary to use certain additional chemicals to keep the water in perfect condition.
Depending on the location and the characteristics of the water, in some cases we have had to add flocculants, phosphate removers or algaecides, as salt chlorination does not solve all problems definitively.
Differences between salt chlorination and traditional chlorine systems
Finally, it is important to highlight the differences between salt chlorination and traditional chlorine systems.
Advantages in chlorine dosing
The main benefit of using salt chlorination is the control over chlorine dosing.
In traditional systems, it was easy to make mistakes in the amount of chlorine added, resulting in uncomfortable conditions for bathers.
Salt chlorination avoids this by keeping the chlorine level constant and adjusted to the actual needs of the pool.
Is salt chlorination more natural than traditional chlorine?
Despite what many people think, salt chlorination pools are not ‘natural’ pools.
As we have explained to many of our customers, salt pools are still chlorine pools, just with a more controlled way of generating the chlorine needed to disinfect the water.
This process has nothing to do with natural purification systems, such as those we use in our natural pools, where plants and biological processes remove impurities without the intervention of chemicals.
