It’s common knowledge that keeping swimming pools clean, healthy to swim in, and safe requires chemicals, but once you really get into it, swimming pool chemicals get complicated, fast. You are, after all, maintaining a medium- to large-sized body of water that is frequently exposed to the weather, the elements, and to large volumes of different people bringing in a mix of bacteria, germs, sunscreens, dirt, and other contaminants. 

Which is why for commercial pool owners, whether you’re managing hotel pools, apartment or condo pools, HOA community pools, aquatic facilities, public pools, or even spas, it helps to keep a swimming pool chemicals list handy to reference. 

Ahead, we’ve broken up our list of go-to pool chemicals by category: sanitizers, pool stabilizer, pool shocks and oxidizers, pH balancers, algaecides, and specialty chemicals. 

As always, chemicals are chemicals and should be stored and handled safely and according to the recommended safety specifications. The CDC also recommends in their Model Health Code that all pool chemicals you use should be certified, listed, and labeled to either NSF/ANSI 50 or NSF/ANSI 60 and disinfectants and algaecides should have an EPA FIFRA registration. You can find an in-depth explanation of NSF/ANSI certifications in our article on pool test kits.

Sanitizers

First, we have sanitizers, also referred to as disinfectants. These arguably may be the most important pool chemicals to keep in stock at all times, although they also work in tandem with other pool chemicals. Sanitizers keep pool water clean by killing and controlling bacteria, viruses, other microorganisms, and even algae, allowing the water to be safe to swim in. 

• Chlorine: Chlorine is the most popular and widely used pool sanitizer, and even saltwater pools disinfect by transforming salt into chlorine. Chlorine is a powerful oxidizing agent, or oxidizer, which means it has the ability to accept electrons from other molecules. It actually disinfects best when added to water, where it breaks down into hypochlorous acid and hypochlorite ion. These chemicals are then able to break down the cell walls of bacteria and other microorganisms, destroy the enzymes and structures inside, and render them harmless.
  
  Chlorine is available in liquid, granular, and tablet form, as well as stabilized (with cyanuric acid already added) and unstabilized forms. We’ll cover pool stabilizer in the next section, but in general, it’s best to use unstabilized chlorine and add pool stabilizer separately as this will give you more control over the chemical balance in the pool water.
  
  The CDC recommends commercial pools and aquatic venues maintain a minimum DPD-FC (Free Chlorine) concentration of 2.0 ppm (mg/L) for pools using pool stabilizer. For pools not using stabilizer, for example, protected indoor pools, a minimum DPD-FC concentration of 1.0 ppm (mg/L) is recommended. Spas should maintain a minimum DPD-FC concentration of 3.0 ppm (mg/L).
  
  As an oxidizer, chlorine is also highly reactive and can be dangerous if not stored, handled, or used properly. They will quickly create an oxygen-rich environment that can make them more combustible, and fire and explosions worse. It’s critical to store chlorine and other oxidizers separately from other pool chemicals–especially acids–and to keep them away from moisture, water, sunlight, and extreme temperatures.
  
  
• Bromine: Bromine is an alternative to chlorine as a sanitizer or disinfectant, is gentler on skin and eyes, and creates less of an odor. It can maintain sanitizing levels at a higher pH range than chlorine, but will also degrade faster in sunlight than chlorine. For these reasons, it’s more popular in spas, hot tubs, and indoor pools, though it’s also more expensive than chlorine.
  
  Bromine is in the same chemical family as chlorine and disinfects similarly. When added to pool water, it creates bromamines, which break down and neutralize microorganisms and organic contaminants.

You can apply bromine in tablet form or granular form, or it can also be generated on-site through a 2-part system that involves adding either liquid or granular sodium bromide that creates bromide ions in the water. For the second part, you’ll need to add an oxidizer, which can be chlorine but is most typically potassium monopersulfate. This reacts with the bromide ions to create hypobromous acid (HOBr), which becomes the water’s active sanitizer.

For pools and aquatic venues using bromine to disinfect, the CDC recommends a minimum bromine concentration of 3.0 ppm (mg/L), while spas should maintain a minimum of 4.00 ppm (mg/L). Bromine concentrations should at any time exceed d 8.0 ppm (mg/L) whenever the pool or spa is open to guests and swimmers.

Bromine is also an oxidizer, so should be stored and handled carefully in the same manner as chlorine. 

Pool Stabilizer

When you add chlorine alone to outdoor pool water (also referred to as unstabilized chlorine), sunlight causes it to dissipate quickly and rapidly lose its sanitizing power. Cyanuric acid (CYA) is known as pool stabilizer as it combines with chlorine to help protect it from solar degradation. 

It works by binding to chlorine molecules and forming a protective barrier around them, while still allowing the chlorine to effectively disinfect the water. 

While you can simply use stabilized chlorine–which is chlorine with the stabilizer already added–the chlorine gets used up in pool water leaving  the CYA and can eventually reach levels high enough to cause “chlorine lock,” where you end up adding more chlorine, more frequently to try to combat this because the chlorine is less effective.

Adding unstabilized chlorine and pool stabilizer separately gives you more control over the careful balance of your water chemistry, making it overall easier to maintain. It’s typical to only need to add stabilizer once, at the beginning of the pool season. 

However, you may need more if you add water following large volumes of swimmers, for example, on holidays, or large rains. Frequent testing for CYA levels is important throughout the season. 

As an acid, pool stabilizer should be stored separately from chlorine and other chemicals and handled carefully. It’s best advised to add CYA to dilute in a bucket of warm water, to avoid accidentally splashing on skin and to prevent damage to pool liners.  Tip: NEVER add water to chemicals, always add the chemical to a bucket of water.

For bromine pools, CYA does not stabilize the bromine like it does chlorine. As we mentioned, because sunlight also degrades bromine even faster, this is one of the reasons bromine is more popular for spas and indoor hot tubs. A chemical called Dimethylhydantoin (DMH) is sometimes added to bromine tablets to provide a small degree of stabilizing protection. 

Pool Shocks and Oxidizers

As chlorine breaks down and kills microorganisms and other organic contaminants, it creates a byproduct called chloramine. These chloramines stay in the water until something else breaks it down. Chloramines are responsible for the ‘chlorine smell’ in a pool and can cause breathing issues such as asthma if left unchecked.

It should be used at the opening and closing of the pool season, as well as following large swimmer volume days and heavy rainfall, to help break down and control algae and bacteria. 

There are a few different pool shock options. Learn more here.

• Sodium Di-Chlor: Sodium Di-Chlor typically contains 55-62% chlorine and quickly dissolves in water to sanitize. It also is pH neutral, so won’t impact pool water pH much, if at all.
• Calcium Hypochlorite (Cal-Hypo): Cal-Hypo also contains chlorine (up to 65%) and is readily available and affordable. However, it does add calcium to your pool water and should not be used in pools with pH levels that measure 7.8 or higher before shocking. It should also not be used in pools with high measurable calcium levels. It’s also not as quick-dissolving as other pool shocks. 
• Liquid Chlorine (Sodium Hypochlorite): Liquid chlorine is readily available, highly effective, and affordable, and is especially popular as an algaecide. It does have a high pH of 13. 
• Non-Chlorine Oxidizer: Non-chlorine oxidizer, or monopersulfate, uses oxygen to effectively sanitize and prevent chloramines from building up in the water. It can also help remove oils, such as from skin and sunscreen from the water and help improve water quality. This type of oxidizer does not kill algae or bacteria and is best used for eliminating chloramines in indoor pools. DO NOT use this for shocking a pool after body fluid contamination like solid stool or diarrhea.

pH Balancers

Water pH is a critical part of maintaining balanced pool water, and should be kept in the ideal range of 7.0 to 7.8. In this range, it’s neither too acidic nor too alkaline (or basic), which helps prevent corrosion and scaling, prevent algae growth and cloudiness, maintain water comfort for swimmers, and ensure chlorine is able to effectively sanitize. 

Maintaining pool water total alkalinity between 80 and 120 ppm is your best defense against a fluctuating pH, as is keeping pool water clear of debris and organic matter. 

However, from time to time, you may find you need to add pH balancers, or adjusters, to bring it back down or up to that ideal range. Approved pH adjusters listed by the CDC’s Model Health Code include (but are not limited to) muriatic (hydrochloric) acid, sodium bisulfate, carbon dioxide, sulfuric acid, sodium bicarbonate, and soda ash.

pH decreasers:

A high pH indicates alkalinity, which means you need to add acids to decrease the pH. If you need to decrease total alkalinity, these acids are commonly used as well.

• Muriatic acid is widely used to lower pH levels as it’s effective and affordable. However, it’s highly corrosive and dangerous to handle.
• Sodium bisulfate is another common type of acid used to lower pH. As a dry form of acid, it’s safer to handle than liquid muriatic acid, but it does add sulfates to the pool water as well.

pH increasers:

Conversely, a low pH indicates water that is too acidic, so you will need to add a substance (a base) to increase alkalinity and/or pH. 

• Soda ash is safe and effective at raising both pH and total alkalinity. It needs to be first dissolved in a bucket of water, then added to pool water. 
• Sodium bicarbonate (also known as baking soda) should  be used if you only want to raise pH as it has less of an effect on alkalinity.  Sodium bicarbonate also needs to be dissolved first in a bucket of water, then added to the pool.

Algaecides

Keeping pool water balanced, clearing debris, and regular cleaning and brushing goes a long way towards preventing algae growth. That said, at times, you may have a stubborn case of algae or tricky conditions that take a harsher approach. There are a few different types of algaecide chemicals you can turn to, some that prevent and destroy algae and some that are only effective as preventatives. These include:

• Quaternary ammonia, also referred to in this use as quat algaecides, are inexpensive and effective, operating as a surfactant in the water to lower the surface tension of the water, which splits open algae cells and kills them. These can be used as a preventative, but not to kill existing algae. 
• Polyquats contain a higher concentration of ammonium chloride salts (30-60%) than quaternary ammonia, and can be effectively use to both prevent and kill existing algae of all types. 
• A safety note about quats: However, it’s important to limit exposure to quats for yourself and your staff, as increased exposure also increases the risk of toxicity and health damage. 
• Mineral-based algaecides contain either copper or colloidal silver to create residuals on the interior surfaces of your pool and prevent algae growth, as well as kill existing algae. 
• Sodium borate can also be used as an algaecide, as it stops algae’s photosynthesis process, effectively killing them. 

Specialty Chemicals to Keep on Hand

In addition to these essential pool chemicals, there are a few other specialty chemicals to keep on hand, including:

• Clarifiers which clear up cloudy water,
• Specialty tile and vinyl cleaners that can break through grease and oils and help you clean scum and calcium deposits from pool surfaces,
• Filter cleaners designed to remove minerals, metals, oils, and other elements from pool filters, and
• Metal removers that remove minerals and metals, including iron, calcium, and copper, and help prevent staining.

Key takeaways on Swimming Pool Chemicals

Even for saltwater pools, maintaining healthy, clean, and safe pool water takes a careful balance of several different types of chemicals–and it’s important to understand them, their uses, and, most importantly, how to store and handle them safely. 

Employing a certified pool operator, or taking the course yourself, will ensure you have the knowledge on hand about these chemicals. This should also be the person on your staff who is responsible for educating the rest of the staff about their use, monitoring safe handling, and ensuring safety details are clearly posted near them at all times. 

Accurate testing is another critical step that will ensure you know where your levels are at all times and add the right chemical at the right dosage–which will also help control your chemicals costs. 

It’s why we recommend the NSF/ANSI certified LaMotte WaterLink Spin Touch, which is certified to Level 1 Accuracy and performs all water tests automatically in 60 seconds, making it fast and virtually removing all degrees of human error. Together with the Pool Shark H2O app, you can ensure pool water tests are performed reliably and accurately–and our app will also perform the complex chemical equations for you, ensuring you’re adding the correct dose of the correct chemical and then digitally locking the records for Health Department compliance.