water treatment chemical (calcium hypochlorite 70% 7tablet)

Calcium hypochlorite is an ionic compound with the formula Ca(ClO)2. According to the book "Chemical Principles, the Quest for Insight," it's a weak base that raises the pH of water when it dissolves. Calcium hypochlorite is available as powders or tablets and is often used in water treatment, especially pool chlorination

Calcium Hypochlorite in Water
 

 Calcium hypochlorite is often used to disinfect pool water. Calcium hypochlorite is an ionic compound with the formula Ca(ClO)2. According to the book "Chemical Principles, the Quest for Insight," it's a weak base that raises the pH of water when it dissolves. Calcium hypochlorite is available as powders or tablets and is often used in water treatment, especially pool chlorination

Calcium hypochlorite acts as a weak base, meaning that the hypochlorite ions can pick up hydrogen ions from the water to become hypochlorous acid (HClO). Because pH is the negative log of the hydrogen ion concentration in water, the hypochlorite ions decrease the hydrogen ion concentration, thereby increasing the pH. Calcium hypochlorite is similar in this regard to sodium hypochlorite, the active ingredient in chlorine bleach. However, sodium hypochlorite has one hypochlorite ion while calcium hypochlorite has two.

Effects
Hypochlorous acid is highly toxic to bacteria, so when chlorinating pools or treating water, it's generally best to adjust the pH so hypochlorous acid will predominate in the solution rather than the hypochlorite ion. As the pH decreases, more of the hypochlorite ions pick up protons to become hypochlorous acid. However, in an alkaline solution, less hypochlorous acid will be present. If the water becomes too acidic, however, it will be unfit for swimmers, so pool operators generally try to maintain pH at a slightly alkaline level to ensure an optimum concentration of hypochlorous acid without any of the problems associated with acidity.