Types of Sanitizers

Pool sanitizer helps keep pool water clean and safe and is an essential aspect of pool maintenance.

There are various types of sanitizers available, each with its own benefits and drawbacks. The most popular sanitizer is chlorine. Alternative options include bromine, biguanide, hydrogen peroxide, salt water pool systems, UV pool systems, ozone pool systems, and pool ionizers.


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What Is A Pool Sanitizer?
Types of Pool Sanitizers
     Pool Chlorine
     Pool Hydrogen Peroxide
     Salt Water Pool Systems
     UV Pool Systems
     Ozone Pool Systems
     Pool Ionizers


What Is A Pool Sanitizer?

Every swimming pool must use sanitizer to keep pool water safe and sanitary. Although all sanitizers eliminate harmful pathogens, keep algae at bay, and keep your pool clean, each type has its own features and chemical components.

Choosing the right swimming pool sanitizer depends on your personal preferences, how much money you want to spend, and what benefits you’re looking to achieve.



Types Of Pool Sanitizers


Pool Chlorine

Chlorine is the most commonly used pool sanitizer as it is the least expensive and very efficient at killing bacteria and algae.

Through a series of chemical reactions, chlorine releases hypochlorous acid to break down the cells in harmful bacteria to inactivate them. When it combines with contaminants, it creates chloramines and stops working as a sanitizer. The chloramines cause a strong chlorine smell and can irritate skin, eyes, and lungs. This can be resolved by shocking the pool with additional chlorine.

Chlorine is widely available and has relatively low weekly operating costs. Liquid, granular, and tablet types of chlorine are available, all of which are added to pool water in their own way.

Stabilized and unstabilized chlorine are two basic types of chemicals that release chlorine into pool water. Stabilized chlorine (trichlor and dichlor) contains cyanuric acid, which prolongs its lifespan in pool water. Unstabilized chlorines are sodium hypochlorite, lithium hypochlorite, calcium hypochlorite, and chlorine gas. They lack cyanuric acid, making them vulnerable to the sun and more suitable for indoor pools.


  • Very effective at killing algae
  • Widely available
  • Easy to use
  • Economical
  • Available in various forms
  • Chlorine systems require minimal equipment maintenance



  • Strong odour
  • Can cause skin and eye irritation
  • Harsh on clothing
  • Lack of self-regulation, leading to the most amount of maintenance labour
  • Without cyanuric acid, chlorine levels deplete quickly in sunlight



The Different Forms Of Chlorine

You can add chlorine to your pool by using chlorine tablets, granular chlorine, or liquid chlorine.

Chlorine Tablets

Chlorine tablets provide an easy and effective way to sanitize pool water. As long as you maintain the correct number of tablets in your chlorinator, operate the filter system regularly, and set the chlorinator dial to the proper level, you’ll receive a constant chlorine level in pool water.

Chlorine tablets are usually 3” and 1” in size and are placed in your skimmer basket or a floating chlorine dispenser. Slow to dissolve, chlorine tablets maintain the previous chlorine level. Since they have a slightly lower pH than your pool water, you’ll have to adjust your water more often than with granular chlorine.


  • Available either stabilized with cyanuric acid or unstabilized
  • Powerful and effective
  • Provides a stable chlorine level
  • Tablets are inexpensive, and chlorine dispensers are affordable to purchase, install, and maintain



  • More time is required to dissolve
  • Requires more pH adjustments than granular chlorine


Granular Chlorine

Granular chlorine, also known as pool chlorine powder, requires a little more effort to use as a sanitizer. Following package directions, a certain amount of granular chlorine will need to be added to a bucket of water, then dissolved. The mixture is poured around the pool’s perimeter, with particular preference to return jet locations.

Many pool owners use granular chlorine in conjunction with tablets. Granular chlorine is often used to shock the pool and remove bacteria that are becoming immune to the constant level of chlorine supplied by tablets. If granular chlorine is used alone, the pool is more likely to turn green or cloudy.


  • Works faster than tablets




Liquid Chlorine

Liquid chlorine provides an easy, convenient way to sanitize pool water. You can pour it directly into the pool, with no pre-mixing necessary.

Because it’s pre-dissolved, liquid chlorine for pools requires ample storage space. Pool owners will need to house it in a large storage barrel or make frequent trips to the pool store.

If improperly stored, the percentage of chlorine can degrade quickly.


  • The most affordable option
  • Fastest acting



  • Not stabilized with cyanuric acid
  • Requires a large amount of storage
  • Short shelf life
  • High pH
  • Highly corrosive


How to Use Pool Chlorine

1. Wear Protective Gear

Put on protective goggles and gloves to remain protected from pool chemicals. If adding chlorine to an indoor pool, ensure adequate ventilation before adding the chlorine.

2. Test Pool Water to Calculate Amount of Chlorine

Test your pool water’s pH and chemical levels daily. Read the chlorine product’s label to determine how much chlorine to add based on your pool’s volume. The ideal chlorine level for pool water is 1-3ppm. Always round up to the closest 5,000 gallons.

3. Add Chlorine to Your Pool Water

Calculate the amount of chlorine needed according to the manufacturer’s directions. The method of adding chlorine to your pool water will depend on the form of chlorine you’re using:

Granular Chlorine: Fill a bucket three-quarters full of pool water, then pour the measured amount of chlorine into the bucket. Stir until the chlorine is totally dissolved. Pour around the perimeter of the pool – not directly into the skimmer.

Tablet Chlorine: Chlorine tablets should be added to floating chlorine dispensers, pool skimmers, or automatic pool chlorinators. If using an automatic pool chlorinator, load it with tablets and set the chlorine level between 1-3ppm.

Liquid Chlorine: Measure the appropriate amount, then pour around the pool’s perimeter or above a return inlet.

If your chlorine isn’t stabilized, you’ll have to add cyanuric acid and dilute it according to the package’s instructions. Generally, about four pounds of cyanuric acid is necessary per 10,000 gallons of water to reach 10 ppm. The ideal level for cyanuric acid in pool water is 30-50 ppm.

4. Test and Balance Your Water

Retest the water to ensure it meets the correct balance. Wait the recommended amount of time as per the manufacturer’s instructions before swimming.

How Much Pool Chlorine to Add to Pools

The chlorine level of your swimming pool should be 1-3ppm. If the free chlorine is low (0-0.5ppm), you’ll have to add chlorine. If the free chlorine is high (above 3ppm), avoid swimming and continue testing until your free chlorine is lower.


Pool Bromine

Bromine works similarly to chlorine and is part of the same chemical family. However, unlike chlorine which stops working after producing chloramines, bromine’s interactions result in bromamines, another effective sanitizer.

Bromine is typically more expensive than other sanitizers. Bromine isn’t as irritating as chlorine but is not as stable in sunlight.

Because of its lack of odour, bromine is especially popular in indoor swimming pools. Bromine comes in 1” tablets which contain a small amount of chlorine to provide additional sanitization. It’s also available as a liquid or granule.


  • Almost odourless
  • Less irritating than chlorine
  • Works with all pool types
  • Remains active longer and doesn’t break down as quickly as chlorine
  • Does not corrode steel
  • More effective in hot water environments such as hot tubs



  • Expensive
  • Less oxidation power than chlorine
  • Not as effective in outdoor pools
  • Not as effective as chlorine at killing algae


How to Use Pool Bromine


1. Wear Protective Gear

Put on protective goggles and gloves to remain protected from pool chemicals.

2. Test Pool Water to Calculate Amount of Bromine

Test your pool water using a bromine test kit. The ideal bromine level in a pool is 2-3 ppm, and the pH should be 7.2-7.4 for bromine to work effectively.

3. Add Bromine to Your Pool Water

Calculate the amount of bromine needed according to the manufacturer’s directions. Add a bromine tablet to a skimmer basket, floating dispenser, or feeder. If using a floater, regularly check to ensure it remains out of the skimmer.

4. Test and Balance Your Water

Retest the water to confirm it meets the correct balance. Wait the recommended amount of time as per the manufacturer’s instructions before swimming, usually a minimum of 30 minutes.

How Much Bromine to Add to Pools

Seventeen bromine tablets are necessary for every 10,000 gallons of water. Test the bromine level of your swimming pool weekly and add the tablets whenever needed to maintain a bromine residual of 2-3ppm.



Polyhexamethylene biguanide (PHMB) is a non-chlorine sanitizer that’s peroxide-based. Baquacil is the brand name.

Biguanide causes contaminants to bind together, resulting in insoluble clumps that are more manageable for your pool filter to catch. If the filter gets too clogged up from the clumps, the result can be cloudy pool water. Combining biguanides with algaecides can help with recurring algae problems.

Although biguanide can remove bacteria and algae, adding an oxidizing agent is necessary to remove other pool water contaminants such as sweat, sunscreen, and body oil.

Unlike chlorine, biguanides don’t degrade with sunlight, temperature, or pH level fluctuations. However, they’re not compatible with certain pool chemicals or treatment processes, such as chlorine releasing chemicals, copper algaecides, and potassium monopersulfate, so some health departments have restricted their use.

Over time, microorganisms can build up a resistance in biguanide pools. This sanitizer is also more expensive and requires a higher amount of maintenance.


  • Odourless
  • Fairly stable
  • Can act as an independent sanitizer
  • Suitable for swimmers with a chlorine allergy



  • Decreases in effectiveness over time
  • Can cause cloudy pool water
  • Limited to small, residential pools
  • Works best with sand filters
  • Test strips aren’t consistently accurate
  • Requires an oxidizer specifically for biguanide pools
  • Incompatible with Corona discharge ozone generators, detergents, ionizers, copper and silver-based algaecides, and other popular chemicals


How to Use Biguanide


1. Wear Protective Gear

Put on protective goggles and gloves to remain protected from pool chemicals.

2. Test Pool Water to Calculate Amount of PHMB

Test your pool water using a PHMB-specific test kit. The ideal PHMB level should be 30-50ppm as a 20 percent product, or 6-10ppm active PHMB.

3. Add PHMB to Your Pool Water

Calculate the amount of PHMB needed according to the manufacturer’s directions. Pour the product evenly around the pool’s perimeter with the circulation system running.

4. Test and Balance Your Water

Retest the water to ensure it meets the correct balance. Wait the recommended amount of time as per the manufacturer’s instructions before swimming.

How Much Biguanide to Add to Pools

When the level falls to 30ppm or less (usually after 10-14 days), top up the PHMB to raise the level back to 50ppm.



Pool Hydrogen Peroxide

Hydrogen peroxide is a strong oxidizer that’s 30 percent stronger than chlorine. This powerful oxidizer can be combined with UV light to sanitize swimming pool water.

When hydrogen peroxide for pools reacts with sunlight or artificial UV light, it breaks down to form oxygen radicals. These reactive oxygen radicals can destroy pathogens, cleaning your swimming pool water. Peroxide will convert any contaminants into a solid particle that your filtration system will catch.

A 35 percent concentration of hydrogen peroxide is usually used in swimming pools, although some pool owners prefer a 50 percent concentration.


  • Natural
  • Fast reacting
  • Proven and effective
  • Oxidizes better than chlorine
  • Creates a chlorine-free environment
  • Suitable for swimmers who are allergic to common pool chemicals



  • Doesn’t disinfect as well as chlorine
  • Cannot be used alone; needs to be combined with UV disinfection
  • Large quantities need to be added
  • Inhaling undiluted hydrogen peroxide can pose health risks
  • Incompatible with DE filters


How to Use Pool Hydrogen Peroxide


1. Wear Protective Gear

Put on protective goggles and gloves to remain protected from pool chemicals.

2. Test Pool Water to Calculate Amount of Hydrogen Peroxide

Test your pool water once a week. The ideal range for hydrogen peroxide is 50-90ppm. When levels decrease below 50ppm, add one cup of hydrogen peroxide per 2,000 litres (500 gallons) of pool water.

3. Add Hydrogen Peroxide to Your Pool Water

Calculate the amount of hydrogen peroxide needed according to the manufacturer’s directions. Follow the instructions to determine how to prepare the hydrogen peroxide.

Avoid inhaling the product as an undiluted, very high concentration of hydrogen peroxide is known to pose respiration issues.

4. Let Your Pump Run

Turn your pump on and let it run to filter the pool chemicals thoroughly.

5. Store Your Leftover Hydrogen Peroxide

Store your hydrogen peroxide in a cool, dark place for longer shelf life. Hydrogen peroxide for pools typically lasts one month after being opened and can weaken even faster when exposed to ultraviolet light.

How Much Hydrogen Peroxide to Add to Pools

Add 250 mL (1 cup) of hydrogen peroxide for every 1,000 litres (250 gallons) of pool water. Weekly, test your pool water and add hydrogen peroxide whenever necessary to maintain a level of 50-90ppm.


Saltwater Pool Systems

Using sensors, a saltwater pool’s system automatically converts salt into chlorine. Swimmers are exposed to much less chlorine than in chlorinated pools, which results in not as much skin, hair, and eye irritation. The pool water feels smoother and silkier and does not have the smell of chlorine.

Although the initial investment of a saltwater pool is higher than a traditional chlorine pool, pool owners enjoy up to 50 percent savings in chemical costs over conventional chlorine systems.

To maintain a salt water system, follow the directions in your salt chlorine generator’s operating manual. Usually, the level of salt needed will be 3,000-4,000ppm. Measure your salt levels regularly as part of your routine pool maintenance.


  • Minimal maintenance
  • Water feels softer
  • Reduced skin and eye irritation
  • Gentler on hair and clothing
  • Requires fewer chemical adjustments
  • Recyclable
  • Long-term savings
  • Great for fibreglass pools



  • Expensive up-front cost
  • Corrosive; hard on pool components
  • Unsuitable for vinyl liner pools that have metal walls
  • Abrasive to plaster finishes


How to Use Salt


1. Measure the Current Salt Level

At least 2-3 times a week, test the salinity of your pool with a salt test strip. The ideal range is usually 3,000-3,500ppm, but it depends on your salt chlorine generator.

2. Calculate the Amount of Salt to Use

Review your salt chlorine generator’s operating manual to determine the amount of salt necessary to function correctly. Use a pool calculator to figure out how much water is currently in your pool, then a pool salinity calculator to calculate how much salt to add.

Initially, you should add about 200 pounds of salt for every 10,000 gallons of water.

If you need to lower the salt level in your pool, you’ll need to dilute the water. Drain your pool, then add some fresh water. Determining how much water to drain depends on the pool’s salinity contents.

3. Turn Off Your Salt Chlorine Generator

Locate the switch on your salt chlorine generator and turn it to the off position. Adding salt while the generator is on can result in costly damage.

Your pump can remain on and will help circulate the salt.

4. Add Salt to Pool Water

Snip off the corner of a bag of salt, then start slowly pouring it into the water as you walk around the pool’s perimeter. Try to distribute the salt 1-2 feet away from the pool’s edge in the pool’s shallow end. Use a pool brush to disperse any salt that settles at the bottom of your pool. Do not turn on the generator until the salt is completely dissolved.

5. Let Your Pump Run

Keep your pump running to circulate the water until the salt completely dissolves, usually within 18-24 hours.

It’s recommended that you wait to swim until the salt has dissolved entirely. Salt is not hazardous but can taste or feel unpleasant when it’s not fully dissolved.

6. Measure the Current Salt Level Again

Recheck your salt levels to see that they’re within the ideal range. A salt level below 3,000ppm can reduce the efficiency of your salt generator, resulting in low chlorine production. A high level above 4,500ppm can cause harm to your chlorine generator.

7. Turn Your Salt Chlorine Generator Back On

When you’re finished making any adjustments, locate the switch on your salt chlorine generator and turn it to the on position.

You can resume swimming once the salt chlorine generator is operating again.

How Much Salt to Add to Pools

Check your salt chlorine generator’s operating manual to determine the amount of salt you need to add. Usually, the amount is 3,000-3,500ppm. You’ll need to calculate your pool size first to determine how much salt is necessary to reach the desired level.

It is much easier to add salt than to remove salt. So if you calculated that you need seven bags of salt, put in only six bags, let them dissolve, and then test the water before adding the seventh bag.

pool with floats


UV Pool Systems

Ultraviolet (UV) pool systems inactivate over 99.5% of pathogens and destroy parasites, bacteria, and viruses using a powerful, low-wavelength light. The UV pool system attaches just after the filter and before the jets. UV lamps are long-lasting and often effective for up to 9,000 hours.

Water enters the filtration system and flows into the UV system at a specific flow rate, where up to 60 different types of contaminants are destroyed. The UV light attacks their cell walls, damaging their DNA and ceasing reproduction. The sanitized pool water then returns to the pool via the return jets.

A UV pool sanitizer is a low-maintenance device. Once turned on, it will operate without needing much maintenance or oversight. Since harmful microorganisms are only eliminated when under UV lamps, additional chemicals are necessary to keep the water clean during all other times.


  • Low maintenance
  • Environmentally friendly
  • Reduces chemical usage
  • UV light is inside the filtration system, so it poses no harm to humans



  • Decreases in effectiveness over time – lamp needs replacement
  • Limited sanitation; additional chemicals are still necessary
  • Requires sanitization of piping using chemical cleaners


Ozone Pool System

An ozone pool system uses ozone molecules as powerful oxidizers to chemically destroy contaminants like harmful bacteria.

An Ozonator, or ozone generator, installed in your pool’s circulation system will create ozone gas and diffuse it into the water, most commonly done via venturi injection. Venturi injection is when the generator creates a pressure vacuum. The pressure vacuum draws the ozone gas into the pool water as it circulates through the system. In the water, the ozone reacts when it comes in contact with contaminants like grease, oils, and algae. The contaminants are destroyed, making them unable to reproduce or grow.

Once the water passes through the ozone generator, it returns to the swimming pool via the return jets.

Besides destroying bacteria, viruses, and parasites, ozone oxidizes inorganic and organic chloramines. It can also regenerate the bromide ion, producing another disinfectant.

Like a pool UV system, pool ozone is considered a supplemental disinfectant. As a result, it will need to be used with another pool sanitizer. Occasionally, generator maintenance will be necessary to ensure ozone pools continue working well.

Because of the risk ozone poses to humans and animals, it’s recommended that pool owners install an ozone detection system to monitor and detect high ozone levels. In some locations, a detection system is mandatory.


  • Produces long-term savings
  • Low maintenance
  • Highly compatible; can be used indoors and outdoors, and in above ground and inground pools



  • Ozone is dangerous for humans and animals
  • Expensive initial investment
  • Limited sanitation; additional chemicals are still necessary


Pool Ionizers

A swimming pool ionizer is also known as a pool mineral sanitizer. The pool ionizer releases heavy metal ions like copper and silver into the pool water over several hours to kill bacteria and algae. This electric in-line device is most commonly connected directly to the pump and filtration system but can float in the pool if solar-powered.

Electric ionizers use a cell to create the ions through electrolysis or require mineral cartridges to release the ions into the water. Floating solar pool ionizers work only when there’s sunlight to power them.

Because it is slow-acting, a pool ionizer cannot sanitize independently. Pools using a pool ionizer also require the addition of a chemical sanitizer and an oxidizer.

Most pool ionizer cells can last as long as several years with regular maintenance.


  • Long-lasting
  • Reduces chemical usage
  • Compatible with indoor and outdoor swimming pools
  • Pool water is silkier and smoother
  • Reduction of bad smell or taste to pool water




  • Slow acting
  • Ineffective oxidizer
  • Cannot act as a stand-alone sanitizer
  • Can cause pool staining if improperly configured
  • Requires regular maintenance