Chlorine tablets are a common solution for maintaining water hygiene, particularly in swimming pools and spas. They continuously release disinfectants to control bacteria, viruses, and algae, ensuring the water remains safe and clear for recreational use. These compact forms offer a sustained release of sanitizing agents.
Primary Disinfecting Compounds
Chlorine tablets primarily contain one of two active chemical ingredients: trichloroisocyanuric acid (trichlor) or sodium dichloroisocyanurate (dichlor). Trichlor is found in slow-dissolving tablets for continuous sanitation in larger bodies of water like swimming pools. It provides a high concentration of available chlorine for long-term disinfection.
Dichlor, in contrast, is available in granular form or as faster-dissolving tablets. It is used for shock treatments or in smaller water volumes, such as spas. Both trichlor and dichlor are derivatives of cyanuric acid, contributing to their stability and controlled release of chlorine.
Stabilizers and Other Components
Chlorine tablets often incorporate additional components that enhance their effectiveness. Cyanuric acid (CYA) is a significant additive, functioning as a stabilizer that protects active chlorine from degradation caused by UV light. Without CYA, chlorine would break down rapidly in outdoor pools, requiring frequent reapplication. This stabilizer is often built directly into trichlor and dichlor tablets, releasing into the water as the tablet dissolves.
Tablets may also contain inert binders and fillers. Binders help form the tablet and maintain its structural integrity. Fillers ensure consistent density and a uniform dissolution rate, allowing for a predictable release of active ingredients. These components support the tablet’s form and function without directly participating in disinfection.
The Disinfection Process
When chlorine tablets dissolve in water, they undergo chemical reactions forming disinfecting agents. Both trichlor and dichlor release hypochlorous acid (HOCl) and hypochlorite ions (OCl-) into the water. Hypochlorous acid is the primary active form of chlorine responsible for disinfection. It works by oxidizing and destroying cellular components of harmful microorganisms like bacteria, viruses, and algae, rendering them inactive.
The effectiveness of this process is influenced by the water’s pH level. A lower pH (more acidic water) shifts the equilibrium towards a higher concentration of hypochlorous acid, improving disinfection efficiency. Conversely, a higher pH (more alkaline water) favors the formation of less effective hypochlorite ions. Maintaining water within a recommended pH range is important for maximizing chlorine’s sanitizing power.