Strategies For A Healthy Pool

Photo Courtesy of National Swimming Pool Foundation

Photo Courtesy of National Swimming Pool Foundation

Providing a safe, healthy, disease-free swimming environment can be an overwhelming task for any operator. And without a full understanding of water-chemistry basics, the task will be difficult and next to impossible.

Recreational Water Illnesses (RWIs) are brought into the pool by bathers who do not shower or those who utilize poor hygiene. These RWIs can be contracted by swallowing the pool water, or by penetrating the skin, or just by breathing the vapors (mists) above the water’s surface. Encouraging healthy behaviors before entering the pool will help. For example, facilities should require and enforce showering before entering the pool; swimmers should also be discouraged from urinating in the pool, since the combination of urine and chlorine is dangerous;  the Centers for Disease Control’s (CDC) Six Pleas should be widely posted, urging people who are ill with diarrhea to not swim (see sidebar). These are three important steps for any aquatic facility to follow.

Swimming pools and spas can be a breeding ground for bacteria if the operator does not maintain a constant halogen (chlorine/bromine) residual. It is critical to diligently monitor the pool chemistry parameters. There are two strategies to provide superior water care:

  • Maintain free halogen level to kill harmful bacteria and viruses
  • Maintain proper water balance.

In an effort to ward off bacterial infections, aquatic operators must be precise in maintaining disinfectant levels. Most state and local codes insist on a free chlorine residual of 1.0 parts per million (ppm) to 5.0 ppm for pools, and 3.0 ppm to 10.0 ppm for spas. In addition, there are specific recommendations from the CDC in case of a fecal accident in the pool. (

Chlorine—Free, Combined, And Total

Chlorine is the most common disinfectant, and may be introduced into the pool water through various methods. Most codes require a constant feed apparatus, such as a feed pump or erosion-type feeder. The most common chlorine compounds used in pool operation are sodium hypochlorite (liquid), calcium hypochlorite (granular or tablet), and trichlor (tablet form). Each chlorine type has different reactions in pool water, but all are excellent in killing bacteria if the chlorine level is within the proper range. When added to pool water, the chemical effects of these compounds break down to form hypochlorous acid, which is the active killing form. There is a by-product produced, though, depending on the chlorine compound. For instance, the by-product of sodium hypochlorite is sodium, and the by-product of calcium hypochlorite is calcium. These by-products also impact water chemistry as high calcium increases calcium hardness, which may cause cloudiness.

Photo Courtesy of National Swimming Pool Foundation

Photo Courtesy of National Swimming Pool Foundation

Page 1 of 3 | Next page

Related posts:

  1. Water Chemistry
  2. Pool Water Sanitizers
  3. Pool Genetics
  4. Calcium Saturation Index
  5. Clean Pool Water
  • Columns
  • Departments