Pool Chlorine Types: Comprehensive Guide

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Is Chlorine Necessary in a Pool?

Swimming pools are home to viruses, germs, bacteria and algae, which can make the swimming experience, not just unpleasant, but a health risk and unsafe. How to keep a pool free of pathogens? Is chlorine necessary in a pool?

Chlorine is possibly the most effective and affordable chemical for pool sanitization & disinfection. Chlorine keeps a check on the micro-organisms in the pool so that you can have a safe & enjoyable swim.

Four pool chlorine types are commercially available and are quite popular.

This post is a complete beginner’s guide to the four pool chlorine types with my recommendations on what is best for your pool under different situations. So, let’s dive in.

KEY TAKEAWAYS

• Chlorine sanitizes pools by eliminating germs, bacteria, and algae for safe swimming.
• Four types of pool chlorine include Sodium Hypochlorite, Calcium Hypochlorite, Dichlor, and Trichlor, each with unique uses.
• Chlorine’s effectiveness comes from Hypochlorous Acid, which disinfects by killing bacteria and viruses.
• Free Chlorine sanitizes, while Combined Chlorine indicates contamination; maintain 2-4 ppm of Free Chlorine.
• Cyanuric Acid stabilizes chlorine, preventing sunlight degradation in outdoor pools.
• Regular shocking is essential to combat pathogens and algae during the pool season.
• Alternatives like saltwater systems, bromine, ozone, and UV offer different sanitization benefits.

Does Pool Chlorine Sanitize or Disinfect?

Sanitization & Disinfection are pretty similar. Both Sanitizers & Disinfectants are regulated by The United States Environmental Protection Agency (EPA). EPA defines Sanitizing & Disinfecting as under:

Sanitizing kills bacteria on surfaces using chemicals. It is not intended to kill viruses. 

Source: EPA

Disinfecting kills viruses and bacteria on surfaces using chemicals.  

Source: EPA

Sanitizers are certified for bacteria only, while disinfectants can also be certified to kill viruses, mold, mildew, and fungi. Algae is a form of fungi.

The four Pool Chlorine Types are essentially chlorine-based compounds that react with the pool water to form a weak acid called Hypochlorous Acid (HOCL).

The Hypochlorous Acid (HOCL) sanitizes & disinfects by killing the viruses, germs, bacteria & algae. The acid penetrates the cell walls of the pathogens and makes the cell’s protein backbone dysfunctional. 

In addition, Chlorine is also an “oxidizer”. Which means that chlorine can break down and destroy non-biological contaminants too!

Stabilized vs Unstabilized Chlorine

The Total Chlorine (TC) is the sum of Free Chlorine (FC) and Combined Chlorine (CC) in a pool. 

The combined chlorine (CC) results from free chlorine (FC), combining with the contaminants to form chloramines. Combined Chlorine (CC) cannot sanitize or disinfect anymore. Ultimately it will leave the pool.

The Free Chlorine (FC)  is the active ingredient and available for sanitizing and disinfecting. Unfortunately, Free Chlorine (FC) has a half-life of just 45 minutes under sun’s UV radiation. 

This means that, under sunlight, Free Chlorine (FC) levels will drop from 4 ppm to 2 ppm in the first 45 minutes and then to 1 ppm in the next 45 minutes. To maintain good sanitization the Free Chlorine (FC) level should remain between 2-4 ppm. 

Cyanuric Acid (CYA) – Chlorine Stabilizer

The Cyanuric Acid (CYA) molecule is made up of 3 atoms each of Carbon, Nitrogen, Oxygen and Hydrogen. The chemical formula is C3N3O3H3.

The Carbon & Nitrogen atoms are arranged, alternatively, in a hexagonal ring. The hydroxyl (OH) group is attached to the Carbon atoms. (Refer to Fig 1 below).

CYA protects Free Chlorine (FC) from UV rays by “locking” the unstable hypochlorite ion (OCL-) to the Nitrogen atom in CYA, through a weak bond.

When required, the hypochlorite ion (OCL-) ions disengage and “free chlorine” is available as a disinfectant. Cyanuric Acid (CYA) is a Chlorine Stabilizer.

A Stabilized Pool Chlorine has Cyanuric Acid (CYA) as a a part of its formulation. An Unstabilized Pool Chlorine does not have Cyanuric Acid (CYA) as a a part of its formulation.

Difference Between Shock and Chlorine

As a product Shock and Chlorine are more or less the same thing. The difference is in the dose. Shock is also referred to as Super Chlorination.

To keep your pool sanitized at all times, you must maintain the Free Chlorine (FC) Level in the pool between 2-4 ppm. (The ideal chlorine level is 3 ppm). For this purpose you must ensure either continuous chlorination or atleast daily chlorination.

You must, however, Shock your pool once a week during the pool season. You will also need to shock the pool in case of abnormal increase in pathogens or algae. Shock acts as a disinfectant.

Pool Shock spikes up the Free Chlorine (FC) level from less than 4 ppm to at least 10 ppm (sometimes even to 25 ppm!). This is the “fast & furious” way of killing the pathogens & algae. 

The best time to shock your pool is in the evening after sunset. The high level of Free Chlorine (FC) from the Shock should kill the pathogens & algae, overnight. 

Once the sun is up, the UV rays should burn off the remaining Free Chlorine (FC) and bring the level to 5 ppm or less. This is why it is better if shock does not contain Cyanuric Acid (CYA).

Commonly Used Pool Chlorine Types

Four pool chlorine types are commercially available and are quite popular. Two are unstabilized and two are stabilized. These are:

1. Unstabilized Chlorine
   1. Sodium Hypochlorite (Liquid Chlorine)
   2. Calcium Hypochlorite (Cal Hypo)
2. Stabilized Chlorine
   1. Dichloro-S-Triazinetrione (Dichlor)
   2. Trichloro-S-Triazinetrione (Trichlor)

Lithium Hypochlorite (Lithium Hypo) used to be popular as a pool chlorine, but its production has been discontinued due to the extremely high demand for Lithium from the lithium-ion battery industry.

All pool chlorine types can be used to chlorinate a pool but they differ from each other on several physical, chemical and convenience parameters. I will explain each of them in some depth.

Sodium Hypochlorite (Liquid Chlorine)

Sodium Hypochlorite (Liquid Chlorine) is the salt of Sodium with Hypochlorous Acid. It is sold as a 10-12.5% solution of Sodium Hypochlorite in water, hence the name Liquid Chlorine. It is just a stronger version of the household Bleach, which is a 6% solution

The chemical formula for Sodium Hypochlorite is NaOCl and it’s reaction with pool water is represented as 

NaOCl + H2O => NaOH + HOCL

Sodium Hypochlorite is widely used in swimming pools, especially as a shock.

Liquid Chlorine is a 10-12.5% solution of Sodium Hypochlorite and offers the following advantages as a Shock:

1. High concentration of Available Chlorine (AC)
2. Being in liquid form it mixes and disperses fast
3. Does not raise the Cyanuric Acid (CYA) level of the pool
4. Does not increase the Calcium Hardness (CH) level
5. Cost Effective and Easy to Use

Calcium Hypochlorite (Cal Hypo)

Calcium Hypochlorite (Cal Hypo) is the salt of Calcium with Hypochlorous Acid. It is usually sold as a granular powder but is also available as “slow dissolve” tablets. Cal Hypo, for pool use, typically has 65-70% Available Chlorine (AC). 

The chemical formula for Calcium Hypochlorite is Ca (OCl)2 and it’s reaction with pool water is represented as 

Ca(OCl)2 + 2H2O => 2CaOH + 2HOCL

Calcium Hypochlorite has a very high concentration of Available Chlorine making it a good choice as Pool Shock. But, it does have some disadvantages. 

Cal Hypo Shock is not recommended for use in:

1. Salt water pools due to the calcium content
2. Painted, vinyl & fiberglass pools due to strong bleaching action

Cal Hypo Shock will also increase Calcium Hardness (CH) levels and may result in cloudiness, turbidity and scaling.

Dichloro-S-Triazinetrione (Dichlor)

Dichloro-S-Triazinetrione is better known as Dichlor. It is usually sold as a granular powder but can also come as tablets.

Dichlor is manufactured by the chlorination of Cyanuric Acid (CYA). The chemical formula of Dichlor is (C(O)NCl)₂(C(O)NH). Symbolically, and easier to visualize, it is:

Dichlor Shock is convenient to use as it can be sprinkled on the pool surface, added to the skimmer or  pre-dissolved in a bucket of pool water and poured into the pool.

Dichlor Granular has a very high percentage of Cyanuric Acid so it is a great way to get both Free Chlorine (FC) and Cyanuric Acid (CYA) level up really fast.

Of course you should not be using Dichlor shock if the Cyanuric Acid (CYA) level of your pool is already high.

Trichloro-S-Triazinetrione (Trichlor)

Trichloro-S-Triazinetrione is better known as Trichlor. It is most commonly sold as 1” or 3” tablets for sanitizing home swimming pools. Trichlor is the richest source of chlorine as it has 90% available chlorine.

In the original powder form, it is used as a disinfectant, bleach or processing chemical, in some industries.

Trichlor is manufactured by the chlorination of Cyanuric Acid (CYA). The chemical formula of Trichlor is (C3Cl3N3O3). Symbolically, and easier to visualize, it is:

Trichlor tablets are designed to dissolve very slowly so that they will last for around a week in the pool. Trichlor tablets can be placed in the Pool Skimmer, in Floating Chlorine Dispensers or in  an Automatic Chlorinator.

Trichlor tablets are certainly the most convenient way to sanitize your pool regularly. With the Trichlor tablet, you can “set & forget” for a week. 

Another advantage is that you can continue using the pool while the Trichlor tablet is steadily sanitizing it. There is no downtime!

Trichlor tablets can not be used to shock a pool as it dissolves slowly and will increase  Cyanuric Acid (CYA) levels.

Safety Precaution: Trichlor and Cal Hypo should never be allowed to come in contact with each other. Cal Hypo is explosive when it comes in contact with even traces of Trichlor.

Recommended Swimming Pool Chemicals

Best Liquid CYA Free Pool Shock

Austin’s Pool Tech Pool Shock (Sodium Hypochlorite) Pool Shock (12.5%) is easy-to-use, fast, and effective. This Pool Shock does not have Cyanuric Acid (CYA-stabilizer) and will not result in build-up of scale. Order from Amazon using the link below:

Cyanuric Acid-Free Shock (Liquid Chlorine) – Liquid

Best Cal-Hypo Pool Shock

Use HTH 52037 Pool Care Shock Advanced chlorine granules, from HTH, for hard-hitting immediate results! Non-stabilized formula is ideal for super shocking or everyday use as it does not contain any Cyanuric Acid (CYA). Order from Amazon using the link below:

Cyanuric Acid Free Shock (Cal Hypo) – Powder

Best Dichlor Granular

Doheny’s Chlorine Di-Chlor Shock comes with added benefits of containing bactericide, algaecide, and disinfectant. It has a long shelf-life and low odor. It is pH neutral and 100% soluble. Order from Amazon using the link below:

Calcium Free Shock (Di-Chlor)

Best Trichlor Tablets

HTH 42055 Pool Care 3″ Chlorine Tabs Advanced come with added benefits of containing bactericide, algaecide, and disinfectant. It is slow dissolving with 90% available chlorine. The dosage is 1 tablet per 10,000 gallons of pool water which lasts for up to one week. Order from Amazon using the link below:

Pool Sanitizer (Trichlor)

The 4 Types of Pool Chlorine Compared

Feature	HTH 3″ Chlorine Tablets Advanced	Doheny’s Chlorine Di-Chlor Shock	HTH Shock Advanced	Austin’s Pool Tech Pool Shock
Type	Trichlor	Dichlor	Cal Hypo	Sodium Hypochlorite
Form	3″ Tablets	Granular	Granules	Liquid
Available Chlorine	90%	56% or 62%	65-73%	12.5%
Stabilized	Yes	Yes	No	No
pH	~2.8	~6.5	~10.8	~13
Use	Daily Sanitizing	Shock, Startup, Daily (small pools)	Shock	Shock

KEY TAKEAWAYS

Trichlor tablets are best for daily sanitizing due to their slow-dissolving nature and high chlorine content.

Trichlor are acidic and will lower pH and alkalinity, requiring adjustments. They also increase cyanuric acid levels.

Dichlor is a fast-dissolving shock treatment that can also be used for startup and daily chlorination in small pools.

Dichlor has a nearly neutral pH, making it gentler on water balance. However, it is stabilized and will increase cyanuric acid over time.

Cal Hypo is a powerful, unstabilized shock treatment that is very effective at killing algae.

Cal Hypo has a high pH and will raise calcium hardness levels. It is also highly volatile and should be handled with caution.

Sodium Hypochlorite (liquid chlorine) is a cost-effective shock treatment that is unstabilized and easy to use.

Liquid Chlorine has a very high pH and will require significant pH adjustments afterward.

It is important to note that each chlorine type affects pool water chemistry differently.

Choosing the Right Chlorine Type for Your Pool

The right choice of pool chlorine type depends on pool location & chemical composition, climate, and usage patterns.

Based on Pool Location & Chemical Composition

The type of pool you own—inground or above ground—can significantly influence the choice of chlorine. Each pool type has unique maintenance requirements that should be considered.

For effective chlorine use in various pool scenarios, here are the best types of chlorine to consider for each case, along with the reasoning behind these recommendations:

1. Regular Sanitation of an Outdoor Pool

Best Choice: Trichloroisocyanuric Acid (Trichlor Tablets)

Reasoning: Trichlor tablets are ideal for outdoor pools because they dissolve slowly, providing a steady release of chlorine over time.

They are stabilized with cyanuric acid, which protects the chlorine from degradation by UV rays, making them effective for outdoor pools.

This method also simplifies maintenance, as the tablets can be placed in skimmers or floating dispensers

2. Regular Sanitation of an Indoor Pool

Best Choice: Calcium Hypochlorite (Granular Chlorine)

Reasoning: Calcium hypochlorite is a popular choice for indoor pools as the pool is not exposed to sunlight and hence requires little CYA protection.

3. Shocking a Pool with High CYA Levels

Best Choice: Calcium Hypochlorite (Cal-Hypo Shock)

Reasoning: Cal-Hypo Shock is CYA-free and will not add additional CYA to the pool.

4. Shocking a Pool with Low CYA but High Calcium Levels

Best Choice: Sodium Dichloroisocyanurate (Dichlor Shock)

Reasoning: Dichlor is recommended for shocking a Pool with Low CYA but High Calcium Levels as it does not increase the calcium hardness of the pool.

Based on Climate

In sunny climates, UV radiation quickly depletes Free Chlorine (FC) levels. Stabilized chlorine options, such as Dichlor and Trichlor, are ideal for pools in these regions as they contain Cyanuric Acid (CYA), which extends chlorine’s lifespan under sunlight. 

Conversely, in cooler, overcast climates, unstabilized chlorine like Cal Hypo or liquid chlorine may suffice, reducing the risk of CYA buildup.

Based on Pool Usage

Pools with heavy bather loads or frequent use require more robust sanitization. In such cases, a combination of Trichlor tablets for consistent sanitization and weekly shocks with Cal Hypo can effectively manage chlorine levels.

Pool Chlorine Components and Testing

Understanding the key components of chlorine in your pool and using the right testing methods can ensure effective sanitization while preventing unnecessary maintenance issues.

Free Chlorine (FC) and Combined Chlorine (CC)

The two primary measurements for chlorine in pool water are Free Chlorine (FC) and Combined Chlorine (CC).

• Free Chlorine (FC)
  Free Chlorine is the active chlorine available to sanitize and disinfect the pool water. It is your first line of defense against harmful pathogens, bacteria, and algae. The ideal chlorine levels for Free Chlorine range from 2 to 4 ppm, with 3 ppm being optimal for most pools.
• Combined Chlorine (CC)
  Combined Chlorine forms when Free Chlorine reacts with contaminants like sweat, oils, and organic matter, resulting in chloramines. Chloramines are less effective as sanitizers and often cause unpleasant odors and eye irritation. You must try to keep chloramine levels below 0.5 ppm. Regular shocking helps eliminate excess Combined Chlorine.
• Chlorine Residual
  The difference between Free Chlorine and Combined Chlorine is known as the chlorine residual, which reflects the pool’s capacity to continue disinfecting. Always aim for a residual that keeps FC levels within the recommended range.

Testing Kits and Interpreting Results

Regular pool water testing is essential for maintaining ideal chlorine levels. Various types of chlorine test kits are available to suit different needs and preferences.

• DPD Test Kits
  DPD (N, N-diethyl-p-phenylenediamine) test kits are one of the most accurate and commonly used methods for testing pool chlorine. They use a chemical reagent to produce a color change in the water sample, which can then be compared against a chart to measure FC and CC levels. DPD tests are excellent for both colorimetric testing and digital analysis.
• Colorimetric Testing
  Colorimetric tests involve matching the color of the test sample to a scale on the test kit. While effective, these tests can sometimes be subjective, as results depend on the user’s ability to distinguish color changes.
• Digital Testing
  For greater accuracy, digital chlorine testing kits use electronic devices to measure FC and CC levels. These kits eliminate user error and provide precise readings, making them ideal for pool owners who prefer automated solutions.

Frequency of Pool Water Testing
Pool water testing should be done at least twice a week during the swimming season. For pools with heavy usage or exposure to extreme weather conditions, more frequent testing may be necessary.

Safety Precautions for Handling Pool Chlorine

Improper storage or handling of pool chlorine can lead to hazardous situations. This section outlines best practices for chlorine safety and emergency procedures to manage potential risks effectively.

Storage and Handling Tips

Proper storage and handling of pool chlorine minimize risks of accidental spills, explosive chemical reactions, or harmful fumes.

• Pool Chemical Storage Guidelines
  • Store chlorine in a cool, dry, and well-ventilated area, away from direct sunlight and moisture, which can degrade the chemical.
  • Keep pool chemicals, including chlorine, in their original, labeled containers to avoid confusion or accidental misuse.
  • Ensure that chlorine is stored separately from other chemicals, especially acids like muriatic acid, as mixing can cause dangerous reactions.
• Protective Gear
  • Always wear appropriate protective gear, including chemical-resistant gloves, safety goggles, and a mask, when handling chlorine.
  • Avoid handling chlorine with bare hands, as prolonged exposure can lead to burns or irritation.
• Chemical Handling Tips
  • Open containers carefully in a well-ventilated space to avoid inhaling fumes.
  • When mixing chlorine into pool water, always add chlorine to water, not water to chlorine, to prevent splashing or violent reactions.
  • Use a designated scoop or measuring device for chlorine, and never reuse containers or tools for other chemicals.

Refer to the MSDS (Material Safety Data Sheet) provided by the manufacturer for detailed guidelines on safe storage and handling.

Emergency Procedures for Spills and Contact

Despite precautions, accidents can happen. Knowing how to respond promptly and effectively to spills or contact with chlorine is crucial.

• Spills and Cleanup
  • If a chlorine spill occurs, isolate the area immediately and ensure proper ventilation to disperse any fumes.
  • Use a broom or non-metallic scoop to collect solid chlorine spills, and place the material in a clean, dry container for disposal according to local regulations.
  • For liquid chlorine spills, dilute the area with large amounts of water. Avoid using other cleaning agents, as they may react with chlorine.
• First Aid for Contact
  • Skin Contact: Rinse the affected area with plenty of water for at least 15 minutes. Remove contaminated clothing and avoid scrubbing the skin. Seek medical attention if irritation persists.
  • Eye Contact: Flush the eyes with water immediately for at least 15 minutes, keeping the eyelids open to ensure thorough rinsing. Contact a healthcare professional immediately.
  • Inhalation of Fumes: Move the individual to fresh air and keep them calm. If breathing difficulty persists, seek medical help without delay.
  • Ingestion: Do not induce vomiting. Rinse the mouth with water and call a poison control center or doctor for further instructions.

Alternatives to Traditional Chlorine Sanitization

While traditional chlorine remains a popular and effective pool sanitizer, there are alternatives.

Saltwater Chlorine Generators (SWGs)

Saltwater pools have gained popularity as a gentler alternative to traditional chlorination systems. At the heart of these systems is the Saltwater Chlorine Generator (SWG), which produces chlorine through a process called electrolysis.

• How SWGs Work
  SWGs use a salt cell, where a low-voltage current converts dissolved salt (sodium chloride) in the water into chlorine gas. This chlorine gas dissolves into the water, forming hypochlorous acid (HOCl) to sanitize the pool. The process continuously recycles salt, making it an efficient and low-maintenance option.
• Advantages of Saltwater Pools
  • Softer Water Feel: Saltwater pools are known for their softer, silkier water, which is gentler on the skin and eyes.
  • Lower Maintenance: SWGs eliminate the need to manually add chlorine, reducing day-to-day maintenance.
  • Cost-Effective in the Long Run: Although the initial setup cost of an SWG system can be high, the ongoing costs of salt are lower compared to traditional chlorine.
• Considerations
  • Saltwater pools still rely on chlorine, albeit produced in a more automated way.
  • The salt cell requires periodic cleaning and replacement. Over time, the high salinity can cause corrosion in pool equipment, so compatible materials should be used.

Bromine, Ozone, and Other Alternatives

For those seeking non-chlorine options, there are several effective alternatives for pool sanitization, each with unique properties and applications.

• Bromine
  Bromine tablets are an excellent alternative for pools and spas, particularly in warmer water where bromine remains more stable than chlorine.
  • Bromine forms bromamines when it reacts with contaminants, which, unlike chloramines, retain some sanitizing properties.
  • While bromine is gentler on skin and eyes, it is typically more expensive than chlorine and not as effective under UV exposure, making it better suited for indoor pools or hot tubs.
• Ozone Systems
  Ozone systems use an ozonator to produce ozone (O3) gas, a powerful oxidizer that eliminates contaminants in the water.
  • Ozone destroys bacteria, viruses, and algae more effectively than chlorine, but it doesn’t leave a residual in the water, so it must be used in conjunction with a sanitizer like chlorine or bromine.
  • Ozone systems are energy-efficient and environmentally friendly, though their upfront cost can be high.
• UV Sanitation
  UV systems use ultraviolet light to neutralize microorganisms in pool water as it passes through a UV chamber.
  • Like ozone, UV systems are highly effective but do not provide a residual sanitizer. They work best as a secondary layer of defense in combination with low levels of chlorine or bromine.
• Mineral Systems
  Mineral systems use cartridges containing silver, copper, or other natural elements to reduce bacteria and algae growth.
  • These systems require minimal maintenance and can significantly reduce chlorine demand, but they are not stand-alone sanitizers and still require a backup sanitizer like chlorine or non-chlorine shock.
• Non-Chlorine Shock
  Non-chlorine shock products, typically based on potassium monopersulfate (MPS), are used to oxidize contaminants and boost water clarity.
  • While non-chlorine shock is not a disinfectant, it complements other sanitizers like bromine or mineral systems to maintain pool hygiene.

Troubleshooting Common Chlorine Issues

Even with proper pool care, chlorine-related issues can arise, affecting water quality. This section addresses common problems and provides actionable solutions to keep your pool clean, clear, and inviting.

Cloudy Water and High Combined Chlorine

• Causes of Cloudy Water
  Cloudy water is a frequent issue linked to poor water clarity. It can result from high levels of Combined Chlorine (CC), insufficient Free Chlorine (FC), or unbalanced pool chemistry. Additional causes include fine debris, improper filtration, and high Cyanuric Acid (CYA) levels.
• High Combined Chlorine (CC)
  Combined Chlorine forms when FC reacts with contaminants, producing chloramines. Excessive CC not only clouds the water but also emits unpleasant odors and irritates the eyes and skin.
• Solutions
  • Test FC and CC levels using a reliable chlorine test kit and ensure CC is below 0.5 ppm.
  • Use proper shocking procedures to break down chloramines. A shock treatment raises FC levels dramatically, oxidizing CC and restoring water clarity.
  • Improve filtration and vacuum the pool to remove particulate matter.

Chlorine Demand and Loss

• Chlorine Demand
  Chlorine demand occurs when organic and inorganic contaminants consume chlorine faster than it can be replenished. This can leave the pool water unsanitized and prone to algae growth.
• Chlorine Loss
  Chlorine loss is often caused by UV radiation from sunlight, which rapidly depletes Free Chlorine levels. This issue is exacerbated in pools with low or no stabilizer (CYA) levels.
• Solutions
  • Address chlorine lock, a condition where FC is bound and ineffective due to excessively high CYA levels. Drain and dilute the pool water to lower CYA to the optimal range of 30-50 ppm.
  • For chlorine demand, shock the pool with a high dose of chlorine to oxidize contaminants and restore proper FC levels.
  • Use stabilized chlorine or add Cyanuric Acid to protect chlorine from UV degradation in outdoor pools.

Dealing with Algae Outbreaks

• Types of Algae
  Algae outbreaks come in various forms, including green, mustard (yellow), and black algae. Each type requires prompt attention, as algae can quickly spread and compromise water quality.
• Causes
  Algae growth typically results from insufficient chlorine levels, poor circulation, or an imbalance in pool chemistry. High bather loads and warm weather can further exacerbate the issue.
• Solutions
  • Test FC levels and adjust to ensure they are within the recommended range of 2-4 ppm. Shock the pool with a chlorine dose sufficient to kill the algae. Follow up with thorough brushing of pool walls and surfaces to dislodge algae.
  • Use an appropriate algaecide as a preventive measure or to address persistent algae. For severe outbreaks, combine algaecides with chlorine treatments for maximum effectiveness.
  • Improve pool circulation by running the pump continuously during treatment and regularly cleaning the filter to remove dead algae and debris.

Thank you very much for reading the post. I do hope you found it informative and helpful.