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 is always   Billabongs   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 for a commercial pool. We will in most   cases be discussing commercial pools, domestic requirements are less demanding, but generally allied.

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 ADJUSTER
*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

TDS

*WHAT IS TDS

*ACCEPTABLE LEVELS

*SALT

 
TEMPERATURE

*OPERATING RANGE

*EFFECT ON CHEMICAL

ON BACTERIA

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 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

Training Overview

GENERAL AIMS OF POOL CHEMISTRY.

PROVIDE BACTERIA FREE WATER.

PROVIDE ALGAE FREE WATER.

PROVIDE WATER THAT IS NOT IRRITANT TO SWIMMER EYES, NOSE
AND SKIN.

PROVIDE WATER THAT IS AESTHETICALLY PLEASING, FREE FROM TASTE AND ODOUR.

PROVIDE WATER THAT IS IN A PASSIVE STATE TO ITS SURROUNDS.

The Overview of a Swimming Pool

Overview of swimming pools:

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 Billabong procedure on how to treat a 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.) is 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!

Download the Billabong Pebble, Glass Pebble start-up procedure.

Download the Billabong Fibreglass and Vinyl start-up procedure.

Halogens

The halogens are a group of non-metal elements found in group 17 of the periodic table. They include:

Fluorine (F): Highly reactive and used in toothpaste for dental health.
Chlorine (Cl): Commonly used as a disinfectant in swimming pools and water treatment.
Bromine (Br): Used in heated spas, in flame retardants and photography as it is more stable at higher temperatures than Chlorine.

Iodine (I): Essential for thyroid function and used as an antiseptic.
Astatine (At): Radioactive and rare, with limited practical applications.
Tennessine (Ts): Also radioactive and not widely studied.

The word “halogen” means “salt former,” as these elements react with metals to produce various salts. They exist in solid, liquid, and gaseous states at room temperature, making them unique in the periodic table

For our purposes, we are only interested in Chlorine (Cl) and Bromine (Br) as they apply 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 sanitisers (which target pathogens like bacteria and viruses), oxidisers focus on destroying organic contaminants.

Typical bather contaminants come from hair spray, suntan lotion, body oil and perspiration.

 
Common Pool Oxidisers:

Chlorine: Chlorine serves as both a sanitiser (at low levels) and an oxidiser (at higher levels). It effectively eliminates organic matter.

Potassium Monopersulfate, Sodium carbonate peroxyhydrate & Sodium carbonate: These non-chlorine oxidisers are often used for shock treatments. They break down organic waste and enhances water clarity.

Benefits of Oxidisers:

Cleaner Water: Oxidisers remove organic debris, making the water safer and more comfortable for swimmers.

Chloramine Reduction: Oxidisers help break down chloramines (formed when free chlorine reacts with nitrogen-based materials), improving water quality.

Remember to maintain proper oxidiser levels to ensure a healthy and enjoyable swimming experience! If you have more questions, feel free to ask.

SANITISERS.:

Destroy micro-organisims,  (very small individuals, each composed of mutually independent parts which work together to develop and support life)

Typical micro-organisims are bacteria, algae, fungi, and viruses. These again introduced by bathers and external factors.

Chlorine:

Description: Chlorine is the most popular pool sanitiser. 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 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 Disassociation

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

TEST KIT DPD No 3 OR R0003 total chlorine (TC) READING OF
3.2 ppm

The following calculation for combined chlorine is as follows

CC=TC-FC

1.2=3.2-2.0

COMBINED CHLORINE READING OF 1.2 PPM IS IN EXCESS OF ALLOWABLE.

MONOCHLOAMINES, DICHLORAMINES OR TRICHLORAMINES MAY BE PRESENT IN WATER.

CHLORINE CONCENTRATIONS
 
HOCL & OCL CHLORINE LEVELS VERSUS pH

EXAMPLE 1 :

Pool (1) FAC Chlorine 3.0 ppm, pH 7.5 = HOCL of 49.0%

Pool (2) FAC Chlorine 3.0 ppm, pH 8.0 = HOCL of 21.5%

To achieve the same bacteria kill rate in pool (2) as in pool (1), the chlorine level would need to be 6.80 ppm at pH 8.0.

EXAMPLE 2 :

Using the same calculators.

FAC Chlorine 3.0 ppm, pH 8.0 = HOCL of 21.5%. Pool (2) has an active chlorine level of 1.30 ppm when compared to pool (1).

Chloramines

CHLORINE RESIDUALS

FREE AVAILABLE CHLORINE TEST. (FAC)

The chlorine residual present when a DPD 1 tablet or R-0001 + R-0002 liquid test is conducted. This test measures only the free chlorine in the water and indicates the sum of the HOCL and OCL species.

COMBINED CHLORINE TEST. (CC)

This test, DPD 3 or R0003 indicates any chloramines formed by the reaction of free chlorine with ammonia wastes from swimmers. Chloramines are combined chlorine and give the typical chlorine odour noticed at indoor pools.

The combined chlorine test is done on top of the FAC sample.

To calculate the combined chlorine figure, it is CC – FAC = CC

TOTAL CHLORINE (TC)

Total chlorine is not a test as such, but is a mathematical expression.

FAC + CC = TC

Types of chloramines:

Monochloramines in swimming pools are primarily caused by the reaction of free chlorine with nitrogen-containing compounds, such as sweat and urine, brought into the pool by swimmers.

Here are some key points:

Chlorine and Amine Reaction:

In swimming pools, chloramines are formed by the reaction of free chlorine with amine groups present in organic substances, mainly those biological in origin (e.g., urea in sweat and urine).

Ammonia and Chlorine Reaction:

As soon as ammonia enters a chlorinated pool, it reacts with hydrogen ions to quickly form ammonium ion. The ammonium ion reacts with hypochlorous acid to form monochloramines.

Chloramine Buildup:

Chloramines can build up in the water, which means they can build up in the air if there is not enough fresh air surrounding pools and other places people swim in chlorinated water.

Air Movement:

Three things cause the buildup of chloramines in the air:

1) Disturbing the water’s surface (for example, when swimmers move in the water or the water is sprayed through aquatic features),

2) Limiting movement of fresh air over the water’s surface, and

3) Using air handling systems to limit the amount of fresh air brought into the swimming area and limit the amount of air polluted with chloramines exhausted out of the swimming area.

Dichloramines in swimming pools are formed through a series of chemical reactions involving chlorine and nitrogen-containing compounds, such as those found in sweat, urine, and other organic substances introduced into the pool by swimmers.

Here are some key points:

:

Ammonia and Chlorine Reaction: When ammonia enters a chlorinated pool, it reacts with hydrogen ions to quickly form ammonium ion.

Formation of Monochloramines: The ammonium ion then reacts with hypochlorous acid to form monochloramines.

Formation of Dichloramines: Monochloramine reacts with free chlorine to form dichloramines.

Dichloramines are less stable than monochloramines and can rapidly decompose. They can cause unpleasant odors and irritation to swimmers. They also contribute to the familiar “chlorine smell” often associated with swimming pools. Therefore, it’s important to manage and control the levels of dichloramines in swimming pools to ensure a safe and pleasant swimming environment

Trichloramines in swimming pools are formed through a series of chemical reactions involving chlorine and nitrogen-containing compounds, such as those found in sweat, urine, and other organic substances introduced into the pool by swimmers.

Here are some key points:

Ammonia and Chlorine Reaction: When ammonia enters a chlorinated pool, it reacts with hydrogen ions to quickly form ammonium ion.

Formation of Monochloramines:

The ammonium ion then reacts with hypochlorous acid to form monochloramines.
Formation of Dichloramines:

Monochloramine reacts with free chlorine to form dichloramines.
Formation of Trichloramines:

Dichloramine reacts with free chlorine to form trichloramines.

Conditions that determine production and air levels of Trichloramines are believed to depend on the degree of water chlorination, contamination of water by nitrogen-containing compounds (which depends on the number of bathers, as well as their behaviour and hygiene), water temperature, water circulation and ventilation.

Trichloramines are an eye and airway irritant, but are also considered to be a possible cause of asthma in children.

To prevent or remove chloramines:

Minimise contaminants:

Encourage swimmers not to enter the water with diarrhoea, use the toilet before swimming, and avoid peeing or pooping in the water.

Rinse off:

Require swimmers to rinse off before getting into the water.

Optimise air handling systems:

Ensure proper ventilation to reduce chloramine accumulation while keeping heating costs down.

How to remove Chloramines:

Chloramines in swimming pools can cause that infamous chlorine smell, red eyes, and skin irritation. To remove them, consider the following methods:

1. Super-Chlorination: With a stable pH (around 7.2), add enough liquid chlorine to reach approximately 10 ppm. This high level of free chlorine breaks apart ammonia-chlorine bonds, allowing ammonia or nitrogen to gas off the pool surface.
2. Non-Chlorine Shock (MPS): Add a non-chlorine shock to the water.
   
3. MPS helps oxidise chloramines.
4. Ultraviolet (UV) Light: UV systems, commonly used in pharmaceutical industries, can break apart chloramine compounds when exposed to specific wavelengths.
   

Breakpoint Chlorination

Breakpoint chlorination is a critical concept in pool maintenance. It’s the point at which the disinfection demand has been met, and all undesirable contaminants in the pool have been oxidised. Think of it as a tipping point where oxidation is complete, and further additions of shock chlorine or other oxidisers become unnecessary.

Here are the key points about breakpoint chlorination:

Chloramines Removal: Breakpoint chlorination ensures that free chlorine levels are sufficient to fully remove chloramines (combined chlorine) from the pool water. Chloramines occur when free chlorine molecules attach to nitrogen or ammonia, rendering them ineffective. Removing chloramines is essential for water quality.

Threshold Level: Pool owners aim for a threshold level of free chlorine that achieves complete chloramine removal. If you fall short of this threshold, some chloramines and contaminants will persist. If you overshoot, you’ve used more oxidiser than necessary.

Formula: The generally accepted formula for breakpoint chlorination is to add 10 times the level of chloramines (as tested by a DPD test kit).

For example:

If your tested combined chlorine (CC) level is 0.5 ppm, add enough shock to reach 5.0 ppm.

If CC is 1.2 ppm, shock the pool to a level of 12.0 ppm.

Chlorine Types: The amount of chlorine needed depends on the type used:

2lts of 12% bleach adds 6.2 ppm of free chlorine.
500grms of 56% dichlor adds 6.6 ppm of free chlorine.
500grms of 65% calcium hypochlorite (Cal Hypo) adds 7.7 ppm of free chlorine.

Cyanuric Acid: If your pool contains cyanuric acid (used to protect chlorine from UV degradation), adjust the breakpoint calculation. Cyanuric acid limits chlorine activity, but requires less chlorine overall.

Remember, it’s better to add slightly more shock than needed to ensure thorough chloramine removal.

Common forms of Chlorine

Some important information:

The chlorine's described above needs to be addressed:

1. Calcium Hypochlorite contains calcium, so prolonged use will result in an increase in calcium hardness
2. When trichlor is used 0.6 ppm of cyanuric acid is added to the water for each ppm of available chlorine added.
3. Dichlor is 57% cyanuric acid; for each ppm of chlorine added, 0.9 ppm of cyanuric acid is added to the water.

The adjacent products are:

High Strength Non-Chlorine Shock Treatment:

Insta-Boost and Oxy-Boost is a powerful shock treatment that helps maintain water quality by eliminating combined chlorine levels.

Fast Dissolving Oxygen Compound:

The products dissolve rapidly in water, making it convenient for application.

It contains a minimum oxygen content of 13%.

Oxidises Organic Contaminants:

Insta-Boost & Oxy-Boost oxidises organic impurities, helping to keep your water clean and clear.

Application and Dosage:

In salt or chlorine-sanitised pools:Use 500 grams of Insta-Boost & Oxy-Boost to treat 50,000 litres of water.
For fountains:Use 25 grams to treat 5,000 litres of water.
Follow the dosage instructions for non-chlorine sanitising systems.

Important Note:

Insta-Boost & Oxy-Boost is not a sanitisers and does not replace the need for a registered sanitising agent.

Note - The Oxidising agent differ in both products. One is an AstralPool product Oxy-Boost, the other Insta-Boost is a Lo-Chlor product

pH

pH (potential of hydrogen) represents how acidic or alkaline (basic) your pool water is based on the concentration of hydrogen ions. It’s measured on a scale from 1 to 14. As discussed in the Halogen / Chlorine module, pH plays a critical role in ensuring pool water meets the general aims of water chemistry

PROVIDE WATER THAT IS:

BACTERIA FREE.

ALGAE FREE.

NOT IRRITANT TO SWIMMER EYES, NOSE
AND SKIN.

AESTHETICALLY PLEASING, FREE FROM TASTE AND ODOUR.

THAT IS IN A PASSIVE STATE TO ITS SURROUNDS.

Let's discuss pH in more detail, this may be technical in nature, but this is essential to express how pH is calculated and how it is affected by chemical, and environmental intervention.

What is pH?

pH (potential of hydrogen) measures how acidic or alkaline your pool water is.
The scale ranges from 1 (extremely acidic) to 14 (extremely basic).
Most pools aim for a pH between 7.2 and 7.8.

Why is pH Important?

Chlorine effectiveness: Proper pH ensures chlorine works optimally.
Swimmer comfort: Balanced pH prevents skin and eye irritation.
Equipment protection: Maintaining the right pH prevents damage to pool surfaces and plumbing.

Effects of pH Imbalance:

High pH:Causes calcium scaling on pool surfaces.
Reduces chlorine effectiveness.
Leads to cloudy water.
Low pH:Corrodes pool materials (plaster, metals, grout, tiles).
Increases chlorine effectiveness, but risks water being too corrosive.

Testing and adjusting pH:

Regularly test pH using a reliable kit.
To raise pH (if too low), add buffer (sodium bi-carbonate) or soda ash (sodium carbonate).
To lower pH (if too high), add muriatic acid or dry acid (sodium bisulfate).

pH is defined as the negative logarithm of the concentration of H+ ions. As a result, the meaning of the name is justified as hydrogen power.

We know that not all acids and bases react at the same rate with the same chemical compound. Some react violently, others moderately, and still others do not. To quantify the strength of acids and bases, we use a universal indicator that changes color depending on the concentration of hydrogen ions in the solution. In general, the value of acids and bases is used to quantify their strength.

Although less intuitive, the mathematical definition is more useful overall. It states that pH equals the negative logarithmic value of hydrogen ion (H+) concentration.

pH = -log [H+]

The pH level is determined by the activity of hydrogen atoms, which is a good indicator of the acidity or alkalinity of water. The scale ranges from 0 to 14, with 7.0 being neutral. Water with a low pH is said to be acidic, while water with a high pH is said to be basic, or alkaline.

Acids and Bases Review
There are several ways to define acids and bases, but pH specifically refers to the concentration of hydrogen ions in aqueous (water-based) solutions. Water dissociates into a hydrogen ion and a hydroxide.

Water shows amphoteric nature (it can act as both an acid and a base). Two water molecules react to produce hydronium and hydroxide ions:

This is also called the self-ionisation of water. 

This equation can also be represented as;

The reaction can be shifted to the reactants or products, as expected for any equilibrium:

When an acid (H+) is added to water, the equilibrium shifts to the left, and the concentration of OH– ions decreases.
When a base (OH–) is added to water, the equilibrium shifts to the left, and the concentration of H+ decreases.
When calculating pH, keep in mind that [ ] stands for molarity, M. Molarity is measured in moles of solute per litre of solution. If the concentration is given in a unit other than moles (mass percent, molality, etc.), convert it to molarity before applying the pH formula.

The relationship between pH and molarity can be expressed as:

Kw = [H+]  [OH–] = 1 x 10-14 at 25°C
for pure water, [H+] = [OH–] = 1 x 10-7

Kw is the dissociation constant of water

Acidic Solution: [H+] > 1×10-7
Basic Solution: [H+] < 1×10-7

The pH of Acids and Bases
A solution’s pH ranges from 0 to 14.

In conclusion:

Due to the role that pH plays in the efficiency of chlorine and in the effects it can have on pool surface, equipment and reliability of chemical test results. Constant monitoring and adjustment of pH is crucial, we will provide parameters and dose rates in another module. We will discuss how Total Alkalinity acts as a pH stabiliser and is an important component in water chemistry is next.

If you are interested in learning more about this subject, go to the following online resources for a deeper dive.

pH - Definition, Calculation, and Significance (scienceinfo.com)

What Is pH? The pH Formula & Equation | ChemTalk (chemistrytalk.org)

pH Definition and Equation in Chemistry (thoughtco.com)

Hyrochloric Acid Vs Sodium Bisulphate

Hydrochloric Acid (Muriatic Acid):

Pros:Highly Effective: HCl is a potent acid that effectively lowers both pH and total alkalinity in pool water.
Stain and Scale Removal: It can remove mineral deposits, stains, and scale buildup from pool surfaces.
Quick Action: HCl works rapidly to adjust water chemistry.

Cons:Safety Hazard: Handling HCl requires caution due to its corrosive nature.

It can cause burns and respiratory irritation.

Storage and Handling: Proper storage and protective gear are essential.

Cost: HCl is generally more affordable than sodium bisulfate.

Environmental Impact: Disposal of HCl must be done carefully to avoid harm to the environment.

Sodium Bisulfate (Dry Acid):

Pros:Safer to Handle: Dry acid (sodium bisulfate) is granulated and less hazardous than HCl.
Ease of Use: It dissolves easily in water, making it convenient for pH adjustment.
Algae Prevention: Helps prevent algae growth by maintaining proper pH.
Compatibility: Compatible with various pool types and other chemicals.

Cons:Cost: Sodium bisulfate is more expensive than HCl.
Slower Action: It may take longer to adjust pH compared to HCl.
Environmental Impact: While safer, it still produces an acidic solution when mixed with moisture.

Choosing the Right Acid:

Safety First: If safety is a top priority, opt for sodium bisulfate.
Efficiency: If rapid pH adjustment is crucial, consider HCl.
Budget: Consider cost implications.
Long-Term: Evaluate long-term costs and environmental impact.

TOTAL ALKALINITY T.A.

Total Alkalinity (TA), also known as pool alkalinity, is a crucial aspect of swimming pool chemistry. It measures your pool water’s ability to resist changes in pH.

This works by absorbing acids in the water, which prevents those acids from lowering your pH level. 

This is why total alkalinity is often referred to as a pH buffer, as it “shields” your pH from substances that would normally lower it.

Total alkalinity is important because it helps maintain a stable pH level in your pool. The ideal pH level for your pool water is slightly basic, somewhere between 7.2 to 7.8.

This is where chlorine works best without making the water too harsh on your skin, hair, and eyes.

Without total alkalinity acting as a buffer, your pH could fall too low, causing the water to become corrosive to your pool surfaces and equipment.

Conversely, if the pH drifts too high, it can lead to calcium scaling.

The substances that make up your total alkalinity include carbonates, bicarbonates, hydroxides, and cyanurates1. These are often introduced to the water through products that help you adjust pH and alkalinity, as well as chlorine stabilisers.

The ideal total alkalinity level for swimming pools is between 80 and 120 parts per million (ppm)134. When total alkalinity is too low, pH is unstable and may oscillate.

Conversely, when total alkalinity is too high, the buffering effect may cause pH to rise, diluting the sanitising efficacy of free chlorine.

To adjust total alkalinity, you can raise it with buffer (Sodium bicarbonate)  and lower it with sodium bisulfate or muriatic acid.

Regular testing and adjustment of total alkalinity are essential for maintaining a healthy and safe swimming pool environment.

pH Bounce

pH Bounce refers to a cyclic and rapid change in the pH level between acidic and basic conditions of the pool water. When water lacks an adequate buffer, it can experience this pH bounce. Here’s how it works:

High pH: If the pH level is too high (meaning the water is too alkaline), you may notice issues like cloudy water or scaling on pool surfaces.

To address this, you would add an acid—such as muriatic acid or dry acid—to bring the pH down.

Low pH: Conversely, if the pH level drops too low, the water can become corrosive, potentially damaging pool walls, floors, and equipment. In such cases, adding basic substances (like sodium bicarbonate or soda ash) can raise the pH back to the desired range.

Buffering Capacity: Increasing the alkalinity of your pool water helps prevent pH bounce.

Alkalinity acts as a buffer, absorbing the effects of adding both acids and bases. Aim to maintain alkalinity between 60 - 180 ppm for stable pH levels.

Remember that maintaining proper pH and alkalinity is crucial for balanced pool water. If the alkalinity is too low (below 80 ppm), pH bounce can occur, leading to erratic pH

Soda Ash versus Sodium Bicarbonate

pH Level: Soda ash (sodium carbonate) is a highly alkaline substance with a pH level between 11.3 and 11.71. Minimally raises alkalinity, making it suitable when you need a pH bump without significantly affecting total alkalinity (if it’s already in the proper range).

pH Level: Buffer (sodium bicarbonate) has a lower pH level of 8. Commonly used to increase pH and total alkalinity.

Calcium FAQs

What is calcium chloride?

Calcium chloride goes by chemical formula CaCl₂. It’s bonded, calcium and chlorine.

One calcium atom (Ca) two chlorine atoms (Cl)

What is calcium hardness?

Calcium is always present in your pool. Hardness is the measure of how much calcium (or calcium carbonate) is present in your swimming pool water. Excessive calcium in a pool is typically the result of an imbalance in your pool water, and it can result in white, scaly buildup.

What causes excess calcium in a swimming pool?

In most cases, excess calcium happens when your pool water is not properly balanced. Common culprits are high pH, fluctuating temperatures, and evaporation.

How do I find out the calcium content in my swimming pool water?

Our pool testing kits measure calcium along with other important levels such as chlorine, pH and alkalinity. Reagents for measuring calcium hardness will be discussed later

How do you remove calcium buildup from a swimming pool?

Refer to our page dedicated to scaling identification and treatment, billabongpoolservice.com.au/scale