Pool Water Chemistry
Points to consider:
The information given in this module follows guidelines issued by Australian Standards, Queensland. Government Health Water quality guidelines for public aquatic facilities and general industry parameters. This will always be Billabong's policy.There is no definitive set of water chemistry for all pools. Every pool is a separate entity. There is a marked difference in chemical demand for a domestic pool and a commercial pool. We will in most cases be discussing commercial pools, domestic requirements are less demanding but generally allied
Queensland Health's water chemistry protocols are crucial for maintaining water quality and safety in the region. They provide guidelines for monitoring and managing water sources to safeguard public health, the environment, and promote sustainable water practices.
Water quality guidelines for public aquatic facilities, Queensland Health.
Training Topics
Exploring the essential topics of swimming pool chemistry is vital. Proper water balance and knowledge of the key chemical components are imperative to maintain a clean, safe, and enjoyable pool.
pH
Exploring the significance of pH levels in swimming pools is crucial for maintaining optimal water quality. It's essential to understand how to keep these levels balanced to ensure a safe and enjoyable swimming experience.
Cyanuric Acid (stabiliser)
Cyanuric acid (CYA), commonly referred to as a chlorine stabilizer or pool conditioner, is vital for the upkeep of swimming pools. It's important to understand its significance and learn the best practices for its management.
Testing
Testing your pool water is essential to ensure water quality. Accurate testing results in a clean and safe swimming environment.
Overview of a Pool
Let’s explore, an overview of a swimming pool.
Total Alkalinity
Exploring the significance of Total Alkalinity (TA) in swimming pool chemistry reveals its crucial role in preserving water balance.
Totally Dissolved Solids
Total Dissolved Solids (TDS) are crucial for maintaining the quality of swimming pool water. Let's explore the concept of TDS, understand its importance, and learn how to control it effectively.
Chemical Parameters
Proper swimming pool water chemistry maintenance is crucial for ensuring water quality and swimmer comfort. We will delve into the key chemical parameters.
Halogens, Chlorine, Sanitisers
Exploring the role of halogens as disinfectants reveals that this group of chemical elements, which includes chlorine, fluorine, bromine, and iodine, possesses distinctive properties that render them effective in disinfection applications.
Calcium Hardness
Exploring the significance of calcium hardness in swimming pool chemistry is crucial. Calcium hardness denotes the measure of dissolved calcium present in the water of your pool. Understanding its importance is key.
L.S.I. Saturation Index
The Langelier Saturation Index (LSI), or swimming pool saturation index, is a vital element of pool water chemistry. It's important to understand its significance and the methods to maintain it, ensuring a safe and healthy swimming environment.
Pool Turnover
Swimming pool turnover is essential for preserving water quality and guaranteeing a safe, enjoyable swimming experience. Let's delve into its significance.
Training Topics
OVERVIEW OF A POOL
THE STRUCTURE
BASIC AIMS FOR PRESENTATION
THE VOLUME
TURN OVER TIME
CHLORINE
THE PRODUCT
FREE TOTAL & COMBINED
HYPOCHLOROUS ACID HYPOCHLORITE
ION RESIDUAL
CHLORINE CHLORAMINES BREAKPOINT
CHLORINATION TYPES OF CHLORINE
CHLORINE VS SALT CHLORINATION
pH
THE SCIENTIFIC DEFINITION
THE PRACTICAL DEFINITION
A pH SUITABLE FOR POOLS
THE pH OF PRODUCTS USED IN POOLS
TOTAL ALKALINITY
THE NEED
THE ADJUSTERS
THE EFFECTS
ON pH
ON WATER QUALITY
ON EQUIPMENT
CALCIUM HARDNESS
THE NEED
THE PRODUCT
THE EFFECTS
ON WATER QUALITY
ON EQUIPMENT
ON SURFACES
ON SALT CHLORINATORS
LANGELIER INDEX
THE NEED
THE COMPONENTS
CALCULATING THE INDEX
INTERPRETATION OF THE INDEX
CYANURIC ACID
THE NEED
THE EFFECT ON CHLORINE ACTIVITY
APPLICATION FOR POOLS AND SPAS
CHLORINE BLOCK
FREQUENCY OF TESTING
COMMERCIAL POOLS
DOMESTIC POOLS
LOG BOOKS
MICROBIOLOGICAL
TESTING
FOR PLATE COUNT
FOR PSEUDOMONAS AND
AERUGINOSA
FOR E. COLI
(TEST KITS)
PHOTOMETER
COMPARATOR
TITRATION
BALANCE CHARTS
CHEMICAL PARAMETERS
THE IMPORTANCE OF
BALANCED WATER CHEMISTRY
CURRENT CHEMICAL
PARAMETERS
POOL TURNOVER
DISCUSSING THE IMPORTANCE OF POOL TURNOVER.
The Overview of a Swimming Pool
Types of Swimming Pools:
In-Ground Pools:
These are permanent pools built into the ground. They can be made of various materials, including vinyl, fibreglass, or concrete.Vinyl Pools (above ground):
The least expensive option. A frame is erected onto an excavation, and a heavy-duty vinyl liner is installed.
Fiberglas Pools:
Pre-moulded in various shapes and sizes, with steps and benches already in place.
Concrete Pools:
Also known as wet shotcrete or Gunite pools. A plaster finish is applied over the concrete surface.
Pool Shapes:
Lap Pools:
Narrow and ideal for training or exercise. Some are as long as Olympic pools (25 meters).
Recreational Pools:
Typically rectangular, with one end shallow and the other deep enough for diving (9 to 11 ft.). They come in various sizes.Free-form Pools: Organic shapes that blend well into the backyard landscape.
Pool Construction Methods:
Vinyl, fibreglass, and concrete are common choices.
Vinyl pools are cost-effective, while fibreglass pools come pre-moulded.
Concrete pools (shotcrete or Gunite) offer durability and customisation.
Remember, choosing the right pool involves considering your needs, budget, available space, and design preferences. I
What maintenance is required for a swimming pool?
Please refer below for the Billabong procedure on how to treat new concrete pool surfaces and fibreglass pool surfaces.
Regular maintenance is essential to keep your swimming pool clean, safe, and enjoyable. Here are the key tasks for maintaining your pool:
Pool Water:
Keep the water clean, clear, and balanced.
Test and adjust pH levels (7.4 – 7.6).
Maintain free available chlorine (1.0 – 3.0 ppm).
Top up the water level as needed.
Pool Interior:
Regularly clean the pool walls, floor, corners, and ladders to prevent algae and debris buildup.
Address any algae or mould promptly.
Pool Filter System:
Ensure your filter system (cartridge, sand, or *D.E., * which are not in common use) are functioning properly.
Regularly clean or backwash the filter to remove dirt and contaminants.
Skimmers and Returns:
Skimmers pull water into the filter for cleaning. Returns distribute the cleaned water back into the pool. Remember, consistent maintenance ensures a healthy and inviting swimming experience!
HALOGENS
This group of elements, known as the **halogens**
(group 17 of the periodic table), is full of surprises and noteworthy characteristics that make it a fascinating subject of study:
1. **Reactivity and Electron Affinity**
Each halogen has seven electrons in its outer shell, making them highly reactive as they eagerly seek one more electron to achieve a stable, noble gas configuration. This characteristic drives a wide range of chemical reactions, such as forming the salts we use daily—for example, when chlorine combines with sodium, it creates table salt.
2. **Distinct Physical States Across the Group**
There’s an intriguing trend in the halogen family: as you move down the group, the elements progress from gases to liquids to solids at room temperature. Fluorine and chlorine are gases, bromine is a liquid (and is notably the only nonmetallic element liquid at room temperature), and iodine usually appears as a solid with a shiny, lustrous appearance. Astatine, being far down the group, is also a solid, though it’s extremely rare and radioactive.
3. **Key Applications and Impact** - **Fluorine**
is central to modern chemistry. Its high electronegativity not only makes it aggressively reactive but also useful in creating strong, durable compounds like Teflon or in dental products such as toothpaste. - **Chlorine** is indispensable in water treatment and sanitation. Despite its benefits, it’s also had a notorious past—used as a chemical warfare agent during World War I. - **Bromine** finds its niche in flame retardants and certain pharmaceuticals, while - **Iodine** is critical for human health, particularly for thyroid function, and is widely used as an antiseptic in medical settings. - **Astatine**, on the other hand, is so scarce and radioactive that our understanding of it is mostly theoretical, with only minute amounts occurring naturally.
4. **Chemical Bonds and Environmental Roles**
Halogens tend to form diatomic molecules (like F₂ and Cl₂), and their reactions with metals yield a bulk of our familiar salts. Beyond their everyday roles, halogens have environmental implications; chlorine compounds, for example, are central in discussions about ozone layer depletion and the broader impacts of industrial chemicals on our atmosphere.
These facts hint at just a fraction of the halogens' role, from everyday applications to profound chemical properties. If you’re curious about how their reactivities compare or want to dive into how halogens influence environmental chemistry, there’s a wealth of fascinating details to explore. The aspects of the halogen family interests us the most relate to swimming pool sanitation.
They are :
OXIDISERS.:
What Are Oxidisers?
Oxidisers are chemicals that steal electrons from other compounds, breaking them down into their base components. They play a crucial role in pool water treatment. Unlike sanitizers (which target pathogens like bacteria and viruses), oxidizers focus on destroying organic contaminants. Typical bather contaminants come from hair spray, suntan lotion, body oil and perspiration. Destroy micro-organisms, (very small individuals, each composed of mutually independent parts which work together to develop and support life)Typical micro-organisms are bacteria, algae, fungi, and viruses. These again introduced by bathers and external factors.
Chlorine:
Description: Chlorine is the most popular pool sanitizer. It inactivates and kills harmful pathogens like E. coli, making the water safe for swimming.
Forms:
Liquid Chlorine, Chlorine tablets, Chlorine Powder (Granular Chlorine), or Chlorine gas (Chlorine gas is not commonly used in swimming pools, and is extremely hazardous).
All were added directly to the pool water based on chemical test results.
Bromine:
Description: Bromine is an alternative sanitiser. It works similarly to chlorine, but is more stable at higher temperatures
(ideal for Spas).
CHLORINE ADDED TO WATER.
PH of water 7.6
+ pH
39.0 % --------------> 61.0%
HOCL <-------------- (H+) + (OCL-)
- pH
Hypochlorous Acid Hydrogen Ion Hypochlorite Ion
Equilibrium Reaction:
The dissociation of HOCl can be represented as an equilibrium reaction:
HOCl⇌H⁺+OCl⁻
The balance between HOCl and OCl⁻
depends on the pH level:
At lower pH (more acidic conditions), there’s more HOCl (active form).As pH increases, the proportion of OCl⁻
(less active form) rises TEST KIT DPD NO1 OR R0001 / R0002 free chlorine (FC) READING OF 2.0 ppm
CHLORINE DISASSOCIATION
CHLORINE RESIDUAL
Chlorine residual refers to the amount of chlorine remaining in your pool water after it has reacted with organic matter, such as sweat, urine, and other contaminants. This residual chlorine is crucial for keeping your pool clean and free of harmful bacteria, viruses, and algae.
There are three main types of chlorine to understand:
Free Chlorine: This is the amount of chlorine available to sanitize your pool. It’s effective but can be unstable.
Combined Chlorine: Also known as chloramines, this is chlorine that has already reacted with contaminants. It’s less effective and can cause that characteristic chlorine smell.
Total Chlorine: This is the sum of free chlorine and combined chlorine in your pool.
Maintaining the right levels of chlorine residual is essential for effective pool sanitation. The ideal range for free chlorine in swimming pools is typically between 2.0 to 4.0 ppm (parts per million).
Effects of Temperature on Free Chlorine
Temperature has a significant impact on the effectiveness and stability of free chlorine in swimming pools. Here are the key points to consider:
Increased Chlorine Demand: Warmer Water: As the temperature rises, the demand for chlorine increases. This is because higher temperatures promote the growth of bacteria and algae, which chlorine needs to kill.
Rule of Thumb:
For every 12°C increase above 27°C, the amount of chlorine needed to maintain adequate levels can double.
Faster Chlorine Degradation:
Chemical Reactions: Higher temperatures accelerate chemical reactions, including the breakdown of chlorine. This means chlorine will work faster but also get used up more quickly.