When you have your pool serviced, you must use the proper disinfectant. Typically, this is chlorine, which is made into liquid or powder form. However, some professionals prefer gaseous chlorine for their pools. You can add chlorine anywhere in the cycle, but experts suggest you add it right after filtering your pool. Some pools use a chemical feeder, while others use a chlorine tablet.
The main purpose of swimming pool disinfection is to keep the water bacteria and virus-free. Depending on the type of organism, chlorine is either inactivated or oxidized. Chlorine is a powerful oxidizer but isn’t perfect. Secondary systems improve their efficacy and add enzymes to the water to remove organic waste. The most common method is to use a chemical called Dichlor, which is either directly added to the pool water or pre-dissolved in water and poured around the perimeter of the pool.
Bromine is a chlorine alternative for swimming pools. Bromine is slightly soluble in water but is highly soluble in carbon disulfide and aliphatic alcohols. Because of its bleaching property, it is used in swimming pool water for disinfection purposes. Its use in swimming pools has some disadvantages.
Known also as cal hypo, calcium hypochlorite is a common chemical used to disinfect swimming pools and spas. It works by interfering with the function of bacteria and organic pollutants. It does this by bonding with its enzymes and cell components. It is effective at killing bacteria and other harmful organisms while also raising the pH level. Calcium hypochlorite is available readily and is inexpensive. It is soluble in water and is very easy to store.
PHMB, or poly (hexamethylenebiguanide), is a chlorine-free, chemical preservative that is widely used in swimming pool sanitizers. This chemical is similar to hydrogen peroxide but without the risk of toxicity. Biguanide disinfectants are available in a variety of brands and are safe to use in swimming pools. A common biguanide product is Reputex 20. Reputex 20 is supplied as a 20% aqueous solution of PHMB hydrochloride. PHMB attaches to bacteria that cause illnesses in swimmers.
This chemical is not a replacement for chlorine, and a biguanide-based system will require weekly maintenance. It should remain at a constant level of 40–50 ppm and shouldn’t drop below 30 ppm. Biguanide is also used in combination with an oxidizer, which will remove organic pollutants from the water while improving biguanide’s effectiveness against algae.