Salt Water Chlorination - Process


Salt water chlorination is a water treatment method whereby the disinfectant agent is directly generated from the water by means of an electrolytic process. This technique avoids the use of chemical compounds and is particularly well adapted to swimming pools. Salt water chlorination provides many advantages compared with traditional disinfection methods such as:  water quality obtained treatment costs, health impact and easy automatic operation.

Working principle
When an electrolytic process is generated in salt water, chloride ions coming from these dissolved salts are oxidized on the anode surface and combined to form gaseous chlorine which is immediately dissolved in the water.

This process, thus, provides a source of pure chlorine from the water dissolved salts. Once chlorine has been generated it triggers a powerful disinfection process under different chemical forms (hypochlorous acid, hypochlorite ion, etc.). These species neutralize microorganisms and oxidize organic matter and other contaminants. Once the disinfection cycle has ended, chlorine comes back to its original state as a dissolved salt.

This chlorine generation process requires a certain amount of dissolved salts in the water in order to provide a sufficient quantity of chloride ions. In a swimming pool this is easily achieve by adding table salt to the water until a concentration of a few grams per litter (usually 5 g/l) is reached. This small concentration provides, by itself, an antiseptic action and a very pleasant contact with the skin. The latter is one of the most appreciated qualities of a salt chlorinated swimming pool. It has to be said that the salt concentration required is much lower than sea concentration (35 g/l) and even lower than a physiological solution (9 g/l) commonly used in eye care.

Naturalchlor ® systems generate chlorine in line with no need for tanks or dosing pumps and they are capable of generating from a few grams per hour for a private swimming pool to several kilograms per hour required in big installations.

In most cases, as it’s been explained, added salt is a source of advantages. However there exist a number of situations (Olympic swimming pools, drinking water treatment, etc.)  Where salt concentration can’t be altered. In these cases, it is still possible to obtain chlorine from the small amount of natural salts existing in the water. This requires a more sophisticated electrolytic system with much higher chemical performance. Ecochlor® fresh water system has been developed to effectively generate chlorine in such circumstances.




Salt Water Chlorination - Advantages


Chlorine disinfection is much more effective than in a conventional dosing system. Pure form of chlorine, Cl2, is continuously generated in the cell. This led to the formation of high percentage of hypoclorous acid that has a much higher oxidant power than the hypochlorite ion coming from the commercial chlorine products (sodium or calcium hypochlorite). The high chlorine concentration existing in the cell is capable of destroying contaminants, such as chloramines or remains of body lotions, that commercial chlorine can't eliminate. An additional oxidizing effect is provided by the electromagnetic field existing in the cell. The result is a double and more powerful sanitizing effect. As the disinfection occurs continuously in the cell, an exceptional water quality can be obtained even without any residual chlorine level in the pool. Swimming pools treated with salt chlorination are known for their astonishing crystal clear water.


The system avoids the use of chemical products and prevents from isocianuric preservatives exposure. Chlorine is obtained in a pure chemical form that minimizes the formation of toxic by-products. After completing its disinfection cycle, chlorine converts back to salt in the pool. Chemicals storage is no longer needed. The disinfectant power of the process is superior to conventional chlorination due to the strong oxidizing conditions in the cell. Chloraminated compounds, responsible of skin and ocular irritation and of the characteristic "chlorine odor" of conventional treated swimming pools, are destroyed in the cell. The small concentration of salt in the water acts as a natural antiseptic against algae and bacteria and provides.


The salt concentration, close to the human tear salt concentration, provides a very pleasant isotonic sensation to the skin and eyes. The skin no longer swells or dehydrates, the hair does not get dry, and the eyes can be opened into the water without sting. There is no chlorine odor over the skin and no need to take a shower immediately after the bath. Besides, salt composition accelerates tanning.


Chlorine is produced and immediately dissolved in the water automatically. There is no manipulation or storage of chemical products and, therefore, no risk of fire or explosion. The system eliminates the corrosive ambient conditions in the filter rooms, providing better working conditions and longer equipment life span.


Chlorine is generated without preservatives from salt in a renewable process and it becomes salt again at the end of the disinfection cycle. Water is treated without adding any external compound to the water. The local chlorine production avoids CO2 and energy consumption due to transport as well as accidental toxic dumping.




Salt Water Chlorination - F.A.Q.

Why is salt water healthier?

Saltwater is a gentle natural antiseptic which inhibits the growth of organisms in swimming pool water. The sodium hypochlorite produced in this way, although based on the same principle as traditional chlorines, has a significant advantage: according to report number 17,243 of the Consejo Superior de Investigaciones Científicas (Higher Council for Scientific Research; Instituto Eduardo Torroja), "It does not contain artificial colorants or isocyanides which are highly harmful and require strict control of the dosage and of the residual concentrations that appear in the water in the long run". These elements are the cause of eye, skin, ear and nose irritations as well as hair damage, bad smells, etc. Even your suntan will lock more attractive and natural with Naturalchlor salt water chlorinators, thanks to the iodine content of salt water. Furthermore, it eliminates that unpleasant smell typical of indoor swimming pools.

Is Naturalchlor system cost effective?

Yes. The salt chlorination technology used by Naturalchlor is the most economical system to run. It is cheap in comparison with other technologies because the initial investment is recouped in a short time, thanks to savings in the cost of chemicals and maintenance.


Has Naturalchlor technology been sufficiently tested?

This type of equipment has been manufactured in Australia for over 30 years. Salt chlorination technology is the leading system for the water treatment of Australian pools, it is used in around 97% of them. It is currently achieving tremendous popularity and being used increasingly in the rest of the world.

Is it like swimming in the sea?

No. The salt is added to the water, but in low concentrations. Sea water has a saline concentration of around 35,000 ppm. The Naturalchlor system can operate with concentrations of 5,500 ppm. Mildly saline water is definitely much more pleasant for swimmers than sea water. The salinity of the water processed with our system is similar to that of human tears, so opening your eyes underwater in a pool treated with the Naturalchlor system is much more comfortable because the salt levels are similar to those of the human body, around 0.9%. Every day, more and more hotels and public swimming pools around the world are using salt water chlorinators because their customers prefer that pleasant sensation of the water.

Is salt consumption very high?

Salt consumption is negligible; the reactions take place within a closed-cycle in which there is no product loss, as they break down, act and regenerate. This explains why the salt concentration remains constant. However, a certain amount of salt may be lost through filter backwash and heavy rain; for this reason, the salt level should be checked once a year in domestic pools and every two months in commercial pools.

Is the salt corrosive?

Water with such a low concentration of salt is not corrosive, so Naturalchlor treated water has no damaging effects. This is a great advantage over traditional chemical chlorine, whose impurities could indeed damage pool surfaces. Mildly saline water does not affect the filters or pumps of the leading brands and they are guaranteed against corrosion. It does not affect PVC plumbing system either.

Does the Naturalchlor system affect the pH?

Only when the water is extremely alkaline above 30/40 French degrees. Naturalchlor recommends automatic pH control.

What it require any kind of maintenance?

Very little. The calcium in the water will Guild up on the electrodes little by little. Over a 4 – 8 week period, in the case of non self-cleaning equipment, it will be necessary to remove these deposits by cleaning them in a gentle acid solution. This process is unnecessary in self-cleaning models. Commercial models have a semi-automatic system. It takes between five and ten minutes to clean a cell.

How do you calculate the size of your Naturalchlor chlorinator?

It has come to our attention that some professionals are questioning the use of salt water chlorinators for treating commercial pools. We need to remember that chemical products for swimming pools (liquid chlorine, granular chlorine and chlorine tablets) are produced by an industrial electrolysis of sodium chloride. Salt water chlorination is nothing more than a micro-manufacture of this process, with the great advantage that it is produced in situ and does not require colorants, preservatives or isocyanides, which is the case with the traditional industry. The most important thing is to find out the maximum daily chlorine requirement of the facility in question, taking into consideration climatic factors, the number of swimmers and the general state of maintenance of the filtration room and the facility itself, in accordance with the Naturalchlor technical manual. It would be a serious error to calculate the size of the chlorinators bases simply on the volume in cubic meters of the pool itself. For this reason, should you have any queries with regard to size, our technical department is on hand to assist you with any installation advice.