May is Water Safety Month. This month the City of Hazelwood Parks and Recreation Department is bringing you information on the different aspects on how we keep our pools safe for all patrons. The topic for this week is pool chemicals.
Pool chemical composition is one of the most important aspects of running a pool in order to keep everyone safe when visiting. Diseases such as E. Coli, Legionella, Giardia and Cryptosporidium are common germs that can cause serious illness if contracted. However, with the aid and proper maintenance of chemicals such as chlorine, acid, and other filtration systems, these germs do not pose a threat. So how do these chemicals actually work?
Chlorine is a disinfectant that helps sanitize contaminants in the water. It gets rid of harmful microorganisms that may cause illness or irritations. Three different types of chlorine are used: free chlorine, combined chlorine, and total chlorine. Free chlorine refers to the amount of chlorine that has yet to combine with chlorinated water to effectively sanitize contaminants. Combined chlorine is the chlorine chemical that has combined itself to any contaminants in the water. Total chlorine is the sum of combined and free chlorine, which is used to measure the overall effectiveness of the chemicals and filtration system. St. Louis County Health Code states that pools need at least one part per million (ppm) of chlorine, or one pound of chlorine in one million pounds of water (approximately 120,000 gallons). The County recommends being in a range of 2.0 - 3.0 ppm. We try to keep our pools at 2.4 ppm. Chlorinated water is odorless. The "chlorine smell" is a chemical mixture of sweat, body oils and other contaminants. It is recommended to shower off before entering a pool.
Hydrochloric acid is used in all three of our pools. When mixed with water, hydrochloric acid helps fight against algae in the pool. Chlorine will increase the pH level of the water, while the acid helps to bring the pH level down and balance things out. St. Louis County Heath Code recommends a pH range of 7.4 - 7.6, but no higher than 7.8. We aim to keep our pools at 7.4.
The St. Louis County Health Department requires water to be tested for chemical balance every two hours while the pool is in operation. We have developed an electronic form in additional to regular testing to better track all chemicals and maintenance of the pool.
Stay tuned for next week's information on lifeguards and lifeguard training!