Maintaining safe and clean water in pools and spas: Key terms and questions answered

Questions

What are the two primary goals of maintaining proper pool and spa water chemistry?
Explain why bromine is generally recommended for indoor pools or spas only.
Differentiate between the roles of sanitizers and oxidizers in maintaining water quality.
What is breakpoint chlorination and why is it important?
What are the negative effects of chloramines in pool water?
What are the three main forms of chlorine present in pool water?
What is the significance of the Langelier Saturation Index in pool water balance?
Explain the relationship between pH and total alkalinity.
Why is it important to maintain an appropriate level of calcium hardness in pool water?
What are some potential consequences of high total dissolved solids (TDS) in pool water?

Quiz Answer Key

The two primary goals are water sanitation to eliminate harmful microorganisms and water balance to maintain appropriate levels of pH, alkalinity, hardness, and other chemical parameters.
Bromine is highly susceptible to degradation by sunlight, losing up to 65% of its residual in just two hours. Therefore, it is less effective in outdoor pools exposed to significant sunlight.
Sanitizers primarily kill bacteria and algae, while oxidizers break down organic waste products like sweat, oils, and urine, making them easier for sanitizers to eliminate.
Breakpoint chlorination involves adding enough chlorine to completely oxidize all chloramines and other organic impurities in the water. This ensures that the remaining chlorine is in its free available form, which is the most effective for sanitation.
Chloramines are less effective disinfectants than free chlorine, produce an unpleasant “chlorine” odor, and can irritate swimmers’ eyes and skin.
The three main forms are free available chlorine (FAC), combined chlorine (chloramines), and total chlorine, which is the sum of FAC and combined chlorine.
The Langelier Saturation Index predicts the water’s tendency to be corrosive or scale-forming. Maintaining a balanced index helps protect pool surfaces and equipment while ensuring bather comfort.
Total alkalinity acts as a buffer, resisting changes in pH. Low alkalinity can lead to pH fluctuations, while high alkalinity can make it difficult to adjust pH.
Appropriate calcium hardness prevents the water from becoming too corrosive or scale-forming. Low hardness can damage pool surfaces and equipment, while high hardness can lead to cloudy water and scale deposits.
High TDS can reduce chlorine effectiveness, give the water a salty taste, cause a dull appearance, and promote algae growth. It can also lead to inaccurate test readings and other water chemistry problems.

Glossary of Key Terms

Available Chlorine: The amount of chlorine in a compound that is available for disinfection.
Breakpoint Chlorination: The process of adding enough chlorine to completely oxidize all chloramines and organic impurities, leaving only free available chlorine.
Bromine: A halogen element used as a sanitizer in pools and spas, particularly in indoor settings due to its sensitivity to sunlight.
Calcium Hardness: A measure of the concentration of dissolved calcium and magnesium ions in water.
Chloramines: Compounds formed by the reaction of chlorine with ammonia and other nitrogenous compounds in water. They are less effective disinfectants than free chlorine and can cause irritation.
Chlorine: A halogen element commonly used as a sanitizer and oxidizer in pools and spas.
Cyanuric Acid: A chlorine stabilizer that protects chlorine from degradation by sunlight, extending its effectiveness in outdoor pools.
DPD Test: A colorimetric test used to measure chlorine and bromine levels in water.
Free Available Chlorine (FAC): The form of chlorine that is most effective for disinfection.
Langelier Saturation Index: A calculation that predicts the water’s tendency to be corrosive or scale-forming based on pH, alkalinity, calcium hardness, and temperature.
Muriatic Acid: The commercial grade of hydrochloric acid used to lower pH and alkalinity levels in pool water.
Oxidizer: A chemical that breaks down organic contaminants in water, making them easier for sanitizers to eliminate.
Ozone: A powerful gaseous oxidizer used in some pool sanitation systems, although it does not provide a lasting residual.
Parts per Million (ppm): A unit of measurement used to express the concentration of chemicals in water.
pH: A measure of the acidity or alkalinity of a solution, with a scale ranging from 0 (highly acidic) to 14 (highly alkaline).
Sanitizer: A chemical that kills bacteria and algae in water.
Shocking: The process of adding a high dose of a sanitizer (typically chlorine) to quickly eliminate chloramines and other contaminants.
Soda Ash: Sodium carbonate, used to increase pH and alkalinity levels in pool water.
Stabilizer: A chemical that protects chlorine from degradation by sunlight, typically cyanuric acid.
Total Alkalinity: A measure of the water’s buffering capacity, or its ability to resist changes in pH.
Total Dissolved Solids (TDS): The total amount of dissolved minerals, salts, and other substances in water.
Turbidity: A measure of the cloudiness or haziness of water, often used to assess the level of cyanuric acid.
Water Balance: The state in which all the chemical parameters of pool water are within their ideal ranges, preventing corrosion, scaling, and other problems.