What is chlorine and how does it work to keep you pool safe to swim in? It's something that most of us take for granted but without the production or use of chlorine we wouldn't be able to enjoy a refreshing swim in one of the millions of pools around the world. In addition to keeping swimming pools sanitary, chlorine helps keep our drinking water safe so to say the least it's a very important part of our world today.
This very useful element belongs to a group of 5 elements called halogens which is made up of chlorine, fluorine, bromine,
iodine and astatine. The word halogen is derived from the Greek roots Hal (Salt) and Gen (To produce). All of these chemicals produce salt with similar
properties and the most common is sodium chloride (NaCl) or common table salt.
In a salt system the salt water is used to produce chlorine through a process called electrolysis. The currents of electricity are passed through the plates as the salt water passes through the system, resulting in the chlorine (Cl) and sodium (Na) separating. The separated free chlorine acts to keep the pool safety and this is the basic process used in salt water systems that creates low levels of natural occurring chlorine to sanitize swimming pools.
Chlorine kills bacteria and other microorganisms through a basic chemical reaction. The main chemicals produced are hypochlorous acid and hypochlorite ions. These chemicals attack and destroy harmful cells and leave them in an oxidized and harmless state.
This process continues until the molecules are broken down into single atoms or chloramines. Sunlight and other natural processes then remove the chloramines, which means the chlorine levels have to be maintained.
The process is most effective when the pH of the swimming pool water is between 7 and 8; 7.4 is the ideal pH. Water temperature also plays a role in the effectiveness of chlorine. A higher water temperature will require increased levels of chlorine to remove the harmful bacteria and subsequently a lower temperature will require less.
Chlorine can be found in numerous forms and is used in many different applications. It can be very hazardous in liquid or gas form but it is very rare you would find it in this form. The most common form that a swimming pool owner would encounter is in tablet form. Pure tablets are hazardous and should be handled with caution.
There is a very distinct smell when dealing with pure
chlorine that can be unpleasant and even overwhelming. In pool applications it
can cause numerous health issues that include; itchy irritated skin, red or sore eyes, or stuffy nose. A chlorine allergy is often blamed but it’s usually due to a mild
or moderate irritation caused by exposure to the chemical.
There is no doubt that the answer to what is chlorine is that it is a very useful chemical for sanitizing but also potentially dangerous whether it's in pure gas, liquid or solid form. It can cause chemical burns when contacted with bare skin and many other symptoms when inhaled in gas form. Caution should be used when using chlorine or handling it in any form.
SWPS Home Page >
Salt Water Pools FAQ