--- title: Disinfection of swimming pools, whirlpool and spa | ECSA Chemicals description: Learn about effective methods for disinfecting swimming pools, whirlpools, and spas using chlorine-based products, ensuring hygienic and safe water. | ECSA Chemicals image: https://blog.ecsa-chemicals.ch/hubfs/Imported_Blog_Media/Fotolia_82283026_Subscription_Monthly_XL-1200x900-3.jpg --- ### Select your language [Deutsch](https://blog.ecsa-chemicals.ch/de/die-desinfektion-der-schwimmbaedern-whirpools-und-spa-bereiche)  |  [Français](https://blog.ecsa-chemicals.ch/fr/desinfection-des-piscines-bain-a-remous-et-spa)  |  [Italiano](https://blog.ecsa-chemicals.ch/it/la-disinfezione-delle-piscine-idromassaggi-e-spa) [![ecsa chemicals](https://blog.ecsa-chemicals.ch/hubfs/ECSA_Chemicals_April2025/Images/logo.svg) ![ecsa chemicals](https://blog.ecsa-chemicals.ch/hubfs/ECSA_Chemicals_April2025/Images/logo-sticky.svg)](https://ecsa-chemicals.ch/) - [Industrial Chemicals](https://ecsa-chemicals.ch/en/industrial-chemicals/) - [Pharma & Nutrition](https://ecsa-chemicals.ch/en/pharma-nutrition/) - [Flavours & Fragrances](https://ecsa-chemicals.ch/en/flavours-fragrances/) - [Cosmetics & Detergents](https://ecsa-chemicals.ch/en/cosmetics-detergents/) - [Content Hub](https://blog-chemicals.ecsa.ch/en/ecsa-chemicals) - [About us](https://ecsa-chemicals.ch/en/about-us/) En - En - Products - [Industrial Chemicals](https://ecsa-chemicals.ch/en/industrial-chemicals/) - [Pharma & Nutrition](https://ecsa-chemicals.ch/en/pharma-nutrition/) - [Flavours & Fragrances](https://ecsa-chemicals.ch/en/flavours-fragrances/) - [Cosmetics & Detergents](https://ecsa-chemicals.ch/en/cosmetics-detergents/) - [Content Hub](https://blog-chemicals.ecsa.ch/en/ecsa-chemicals) - About us - [ECSA world](https://ecsa-chemicals.ch/en/about-us/the-ecsa-world/) - [Certifications & Quality](https://ecsa-chemicals.ch/en/about-us/quality-and-certifications/) - [Security & environment](https://ecsa-chemicals.ch/en/about-us/safety-and-the-environment/) - [Infrastuctures logistics & services](https://ecsa-chemicals.ch/en/about-us/infrastructure-logistics-and-services/) - [Career](https://ecsa-chemicals.ch/en/about-us/career/) - [We Are ECSA](https://ecsa-chemicals.ch/en/about-us/we-are-ecsa/) - [Catalogs](https://ecsa-chemicals.ch/en/catalogues/) Follow us This is a search field with an auto-suggest feature attached. Search - There are no suggestions because the search field is empty. # Disinfection of swimming pools, whirlpool and spa - [Home](https://ecsa-chemicals.ch/en/) - [Content Hub - Ecsa chemicals](https://blog.ecsa-chemicals.ch/en) - Disinfection of swimming pools, whirlpool and spa 23 June 2021 #### DISINFECTION WITH CHLORINE **Chlorine** is the most widely used disinfectant. It has both a **disinfectant** and **germicidal** action. Based on these characteristics, it is recommended to use chlorine as the only means for disinfecting swimming pools used at commercial level. [![LA DISINFEZIONE DELLE PISCINE ECSA Chemicals](https://blog.ecsa-chemicals.ch/hs-fs/hubfs/Imported_Blog_Media/Fotolia_82283026_Subscription_Monthly_XL-1200x900-3.jpg?width=800&height=600&name=Fotolia_82283026_Subscription_Monthly_XL-1200x900-3.jpg)](https://ecsa-chemicals.ch/en/product/mp-010751/) The **chlorine content** of the pool water must be **between 0.3 mg/l and 1 mg/l of pure chlorine.** This value is sufficient for **perfectly hygienic water**. The prerequisite is a **pH value between 7.0 and 7.4.** For private use of the pool, **three groups of products** are used, with the following chemical / technical characteristics: - [***Sodium hypochlorite***](https://ecsa-chemicals.ch/prodotto/mp-010751/) It is inorganic and liquid with an **[active chlorine content between 13 and 14%](https://ecsa-chemicals.ch/prodotto/mp-010751/)**, which is introduced through a metering pump. Based on the high pH value and the high quantity applied, the influence on the pH value of the pool water is extremely high. The chloride content of about 140 g/l generates an enrichment of the chloride in the water, therefore it is necessary to **pay attention to the fact that the chloride content does not exceed 150 ml/l**, since as this value increases, it also increases the danger of corrosion of the steel parts of the system. By adequately adding clean water, the chlorine content can be reduced. - [***Calcium hypochlorite***](https://ecsa-chemicals.ch/prodotto/mp-010744/) It is a chlorine-based organic solid product in the form of granules or tablets, with an [**active chlorine content of at least 70%**](https://ecsa-chemicals.ch/prodotto/mp-010744/). Dissolved in water, it releases hypochlorous acid and calcium hydrate. Based on its chemical composition, the product is not completely soluble without leaving residues. Therefore, **it should not be poured directly into the tub** (it would generate discoloration spots on any film coating. To overcome this drawback, the granulate is introduced through the filter). In public swimming pools, specific dosers called *Granudos* are used, which mix calcium hypochlorite with sulfuric acid to optimize the pH value, within the established ranges. The granulate has several **advantages**: 1. **Stability** over time (as opposed to sodium hypochlorite in solution where the chlorine content decreases over time). The guarantee of always having a product with 70% active chlorine. 2. With calcium hypochlorite, the **pH value of the pool water rises only marginally** unlike sodium hypochlorite which, by containing soda, raises the pH of the water and requires a greater amount of acid to bring the pH to optimal values ​​of 7.3-7.5. 3. Possibility of **shock treatments or super chlorination** if it is necessary to make a clarification of the water in a short time. 4. **Containment** of the **chlorate** content ![](https://blog.ecsa-chemicals.ch/hs-fs/hubfs/Imported_Blog_Media/Fotolia_46368820_Subscription_Monthly_XXL-1200x900-3.jpg?width=800&height=600&name=Fotolia_46368820_Subscription_Monthly_XXL-1200x900-3.jpg) - [***Sodium dichloroisocyanurate***](https://ecsa-chemicals.ch/prodotto/mp-025173/) It is an organic product based on chlorine, soluble quickly and without residues, with an [**active content between 56 and 63%**](https://ecsa-chemicals.ch/prodotto/mp-025173/). Based on its behavior in solubility, it is particularly suitable for **shock chlorination**. The pH value is not affected by the addition of this product, however, it should be checked regularly. - [***Trichloroisocyanuric acid***](https://ecsa-chemicals.ch/prodotto/mp-026381/) It is an organic product based on chlorine, slowly soluble and therefore suitable for maintenance chlorination, with an **[active content between 75 and 88%](https://ecsa-chemicals.ch/prodotto/mp-026381/)**. Compared to other active chlorine-based substances, such as sodium or calcium hypochlorite, chloroisocyanurates have some chemical characteristics that have led to their increasing use in recent years, to the point of becoming **the most common chlorinating agents** today. The reason for this success lies in the fact that, in addition to releasing the hypochlorous acid responsible for the germicidal action, the chloroisocyanurates also release a certain amount of cyanuric acid, a highly stabilizing agent against **hypochlorous acid**. It is well known, in fact, that the latter decomposes very quickly due to the effect of ultraviolet rays and high temperatures. The problem is obviously more felt in the central hours of the hot and sunny summer days, just when the frequency of bathers is greater. In such conditions, products such as hypochlorites are consumed very quickly, with consequent need for continuous replenishment. The Cyanuric Acid that derives from the decomposition of Chloroisocyanurates slows down the decomposition process very efficiently, allowing both to obtain **medium-long term savings** on management costs, and to have a pool **always with the right concentration of active chlorine**, even in the most critical hours. - [***COMBO tablet***](https://ecsa-chemicals.ch/prodotto/mp-024916/) The product is a slow dissolving tablet also containing flocculating elements and an algaecide principle. The active chlorine [**content amounts to approximately 75%**](https://ecsa-chemicals.ch/prodotto/mp-024916/). This offers the advantage that it can be used by inserting a sand filter system or in the skimmer. - [***Bromine in tablets***](https://ecsa-chemicals.ch/prodotto/mp-015875/) [**Bromine**](https://ecsa-chemicals.ch/prodotto/mp-015875/)is an oxidant like chlorine, which having a greater atomic weight requires a much higher concentration in the pool water but has the same disinfectant action with the [advantage of being odourless and not irritating the eyes and skin](https://ecsa-chemicals.ch/prodotto/mp-015875/). 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