Swimming Pool | From Wikipedia, the free encyclopedia
- A swimming bath, wading, paddling, or simply a pool, is a man-made container filled with water intended for swimming or other water-based recreation. It can be built either above or in-ground, and be constructed from materials such as concrete (also known as gunite), metal, plastic or fiberglass. Pools can be decorative or custom shape and size, or they may be standard sizes, the largest of which is the Olympic-size swimming pool.
- Many health clubs such as the YMCA, fitness centers and private clubs have public pools used mostly for exercise. Many hotels have pools available for their guests. Educational facilities such as schools and universities occasionally have pools for swimming or physical education classes, or competitive athletics such as swim team. Hot tubs and spas are pools with hot water, used for relaxation or therapy, and are common in homes, hotels, clubs and massage parlors. Swimming pools are also used for diving and other water sports, as well as for the training of lifeguards and astronauts.

Chlorine | From Wikipedia, the free encyclopedia
- it is a chemical element with symbol Cl and atomic number 17. Chlorine is in the halogen group (17) and is the second lightest halogen following fluorine. The element is a yellow-green gas under standard conditions, where it forms diatomic molecules. Chlorine has the highest electron affinity and the third highest electronegativity of all the reactive elements. For this reason, chlorine is a strong oxidizing agent. Free chlorine is rare on Earth, and is usually a result of direct or indirect oxidation by oxygen.
- Nearly all chlorine in the Earth's crust occurs as chloride in various ionic compounds, including table salt. It is the second most abundant halogen and 21st most abundant chemical element in Earth's crust. Elemental chlorine is commercially produced from brine by electrolysis. The high oxidizing potential of elemental chlorine led commercially to free chlorine's bleaching and disinfectant uses, as well as its many uses of an essential reagent in the chemical industry. Chlorine is used in the manufacture of a wide range of consumer products, about two-thirds of them organic chemicals such as polyvinyl chloride, as well as many intermediates for production of plastics and other end products which do not contain the element. As a common disinfectant compounds is used more directly in swimming pools to keep them clean and sanitary.

Water chlorination | From Wikipedia, the free encyclopedia
- Water chlorination is the process of adding chlorine (Cl2) or hypochlorite to water. This method is used to kill certain bacteria and other microbes in tap water as chlorine is highly toxic. In particular, chlorination is used to prevent the spread of waterborne diseases such as cholera, dysentery, jaundice, typhoid etc.