What type of chlorine is used to keep public swimming pools clean?

Keeping public swimming pools clean is an integral part of ensuring the health and safety of swimmers. In this process, choosing the right type of chlorine is crucial because it directly impacts the hygienic status of water quality. This article will examine the types of chlorine used in public swimming pools to maintain cleanliness and the factors to consider when making these choices.

Public swimming pools often utilize chlorine-based chemicals to keep the water clean and disinfected. The most commonly used types of chlorine for pool sanitation are:

  1. Chlorine (Cl2): It plays a pivotal role in the history of swimming pool disinfection. Chlorine is a highly effective disinfection method during the early maintenance of swimming pools. However, its use has decreased over time, primarily due to safety issues associated with handling and storage. Therefore, with technological advancements, modern swimming pools are opting for safer and more convenient disinfection methods. Alternatives to chlorine, such as chlorine tablets and liquid chlorine, are becoming increasingly popular. These alternatives are more convenient and safer to use, avoiding the complexities of gas handling and storage.
  2. Sodium hypochlorite, also known as liquid chlorine: This chlorine salt is widely used to disinfect swimming pools. In liquid form, it can be added directly to pool water, effectively killing algae. The active chlorine content of liquid chlorine is generally 10~12%, making it a convenient and efficient disinfectant.

The use of liquid chlorine is relatively simple—just pour it into the swimming pool, and it will quickly have a sterilizing effect. Due to its high active chlorine content, it is an efficient and fast way to purify swimming pool water. However, when using liquid chlorine, ensure that the amount added is appropriate to maintain balanced and safe water quality.

  1. Calcium hypochlorite, also known as granular chlorine: This chlorine, in the form of granules or flakes, is added to swimming pool water, dissolving to release chlorine with a bactericidal effect. The available chlorine concentration of granular chlorine is generally higher than that of liquid chlorine, about 65~70%.

The use of granular chlorine is relatively simple—just sprinkle it into the swimming pool, and it will quickly decompose and release chlorine to purify water quality. Due to its high available chlorine content, granular chlorine has a very effective sterilization effect and is widely used in swimming pool maintenance.

  1. Dichloro and trichloro tablets: These stable chlorides, in granular or tablet form, contain cyanates, which help protect chlorine from being broken down by sunlight. Dichlorine and trichlorine are widely used in daily swimming pool disinfection, and their dissolution rate is slower than hypochlorite.

The cyanuric acid contained in dichlorine and trichlorine prevents chlorine from being decomposed by the sun, maintaining high stability in water. Both forms of chlorine are suitable for daily swimming pool maintenance because they dissolve slowly and last longer.

Choosing the right type of chlorine is critical to maintaining water quality in public swimming pools. Different chlorine products have their own characteristics, and it’s essential to fully understand their advantages and limitations before using them. Regardless of the type of chlorine used, maintaining proper chlorine levels and pH balance is crucial for effective pool sanitation and ensuring a safe and comfortable swimming environment. Regular testing and monitoring of chlorine levels are critical for pool maintenance.