Maintaining Optimal Swimming Pool Water Quality

Posted on Feb 28, 2025 in Chemistry

Why Not Use the Same Water Quality Criteria for Rivers, Beaches, and Swimming Pools?

• Natural marine environments have a higher capacity for purification and renewal than swimming pool facilities.
• Artificial purification is not possible in natural bodies of water.
• There is an increased likelihood of disease transmission and, therefore, a higher health risk in natural bathing environments compared to properly maintained pools.

What Does It Mean When We Say Water Is Physically Clean? Does It Mean the Water Has No Microorganisms?

• Physically clean water is free of suspended particles that cause turbidity.
• No, physical cleanliness does not guarantee the absence of microorganisms.
• Microorganisms, such as bacteria and algae, constantly evolve and grow in pool water.

How Do We Maintain Hygienic and Aesthetic Conditions of Pool Water?

We maintain hygienic and aesthetic conditions through the following:

1. Circulation through filters: Filtration is critical to water quality. Effective disinfection cannot be achieved without proper filtration.
2. Regular water renewal: The water in the pool must be continually renewed, either through circulation after purification or by adding fresh water.
3. Addition of disinfectants: Microorganisms like bacteria and algae develop in pool water and can lead to health issues and an unappealing pool environment. Disinfection eliminates most pathogens found in the water.

How and How Often Should the Water in the Pool Be Renewed?

A daily intake of new water is necessary to replace losses and maintain water quality (at least 5% of the total water volume). Once a year, the pool should be completely drained for cleaning and disinfection of the vessel.

Authorities may limit water renewal and filling when there are water shortage conditions, and they may establish the frequency of emptying the vessels.

Water meters should be installed in the purification plant to monitor the amount of water renewed and recirculated daily.

What Is the Purpose of Disinfecting Pool Water?

• To destroy the maximum number of pathogens.
• To prevent the growth of pathogens that have not been eliminated.
• To maintain a disinfecting power capable of destroying new microorganisms introduced through the air, rain, or by users.

What Is the Water Purification Cycle? What Is Its Duration?

• The water purification cycle is the time it takes to purify all the water in the pool.
• Splash or children’s pools: Less than or equal to 2 hours.
• Multi-purpose or recreational pools: Less than or equal to 8 hours.
• Covered pools: Less than or equal to 5 hours.

Regarding Coagulants-Flocculants Added to Pool Water:

What Products Are Used? How Are They Applied? What Are the Benefits?

• Common sedimentation products:
  • Aluminum sulfate (Al2(SO4)3): Available in liquid, crystal, or powder form. For maximum effectiveness, the pool’s pH should be slightly alkaline. It is very stable during storage, and the dosage depends on the manufacturer.
  • Polyhydroxichloroaluminum (aluminum oxychloride): Available as a solution, and its mechanism of action is independent of the pool’s pH.
• Application methods:
  • Injection into a recirculation loop using a metering pump.
  • Direct application to the pool.
  • Placement in the pool skimmer.
• Benefits:
  • They make the water clearer and more transparent.
  • They improve the efficiency of the filters.
  • They save time and energy.

Objectives of Filtration

• Clarify the water.
• Retain colloidal materials.
• Remove organic matter.

Comparison of Chlorine-Based Disinfectants