Pool Chlorine: All You Need to Know

Pool Chlorine

Pool maintenance takes a lot of work, but it is always easier with some good pool chlorine as it does most of the work for you.

Pool chlorine is the most common pool treatment chemical. It effectively eliminates bacterial, algae, and other pool contaminants by disinfecting the water and oxidizing some of these harmful materials.

As a pool owner, you need to know what pool chlorine is, its different forms, and the best ways to use it on your pool for the best outcomes.

What is Pool Chlorine? 

Pool chlorine is a chemical sanitizer used to clean and disinfect swimming pools and other things like swim spas.

This swimming pool sanitizer comes in either liquid, tablet, or powder form. Chlorine eliminates the bacteria and algae from the water through a chemical reaction.

When added to water, it breaks down into compounds like hypochlorite ions (OCl) and hypochlorous acid (HOCl). These compounds attack the lipids in bacteria’s cell walls, oxidizing and rendering them harmless in just a few minutes.

Besides algae and bacteria, chlorine effectively fights against other pool water contaminants like microorganisms that carry cholera and hepatitis A, sweat, poo, pee, saliva, and most kinds of dirt or debris from the pool’s surroundings.

Forms of Pool Chlorine 

You can get swimming pool chlorine in either liquid, tablet, or powder form. Each of these forms has its merits and demerits and will be ideal for different situations.

1. Liquid Chlorine

Liquid chlorine is the most convenient form for usage as you typically only need to pour it directly into the pool to sanitize it.

Additionally, it is also often more affordable when compared to the other two types and can hence be an excellent option for those looking to buy chlorine in bulk. It is very cost-effective for commercial pool owners.

However, it is often not as highly concentrated as powder or tablet chlorine, meaning you need to use lots of it. Also, it has a pH of around 13, and so you will need to use it very carefully to ensure you maintain the ideal pool pH level of between 7.3 and 7.6.

2. Powder Chlorine

Powder chlorine is commonly referred to as chlorine granules. It is often a highly concentrated form of chlorine. You will first need to dilute the powder by mixing it with water before use.

It is also possible to pour powder chlorine directly into the pool, but you need to be very keen with your measurements to ensure you do not add too much. But the best element about using chlorine in powder form is that it allows you to control the chlorine levels more precisely.

3. Tablet Chlorine

As the name suggests, this form of chlorine comes in small tablets. Like powdered chlorine, the tablets are usually highly concentrated to ensure you do not need to use a lot of them. In most instances, they are added to the pool automatically using a chlorine tablet dispense.

With a reliable chlorine tablet dispenser like the AquaAce Pool Chlorine Floater Dispenser, chlorinating your pool is easy and convenient as there is nothing much you need to do.

Sometimes chlorine tablets will include other things like cyanuric acid, water clarifier, and algaecide necessary for the pool maintenance, eliminating the need to add them separately.

Kinds of Pool Chlorine 

There are two main kinds of pool chlorine: stabilized and unstabilized chlorine. Here the classification is based on whether the chlorine includes cyanuric acid (CYA) or not, and so you should not confuse this with chlorine forms.

1. Stabilized Chlorine

Stabilized chlorine will have CYA mixed in, meaning you do not need to add it separately. This kind of chlorine has decreased burn rate as the CYA protects it from the sun’s UV rays.

Stabilized chlorine is beneficial for swimming pools that are constantly exposed to direct sunlight as it will help ensure you do not need to keep adding more chlorine frequently.

However, it would help if you kept monitoring the cyanuric level using test strips like the Varify Premium Pool and Spa Test Strips to ensure they do not spike, as this can render the chlorine ineffective at cleaning your pool.

There are typically two kinds of stabilized chlorine compounds you can get out there: lithium trichlor, which often comes in powder form, and sodium dichlor, in granular form. Sodium dichlor has up to 62% available chlorine, while lithium trichlor contains up to 90%.

2. Unstabilized Chlorine

Unstabilized chlorine does not include CYA, and so you will need to add it separately if you plan to use it for outdoor pools. Otherwise, you may have to keep chlorinating your pool every few days as it will break down quickly. But, for shaded and indoor pools, it works well enough.

However, the shorter lifespan of this chlorine type makes it ideal for things like shocking your pool or restoring the chlorine levels within a short time, where you need to use large doses of chlorine.

You can get unstabilized chlorine in sodium hypochlorite, lithium hypochlorite, or calcium hypochlorite form. Sodium hypochlorite contains under 12% available chlorine, while lithium hypochlorite has around 35%, and calcium hypochlorite contains the highest at 60%, making it the most popular option.

Read more: Stabilized vs. Unstabilized Chlorine

Methods for Using Pool Chlorine 

Chlorinating your swimming pool is quite flexible as there are several methods you can use depending on the specific chlorine form and kind you are using. Here are the 4 most common ones.

Method 1: Pour Directly into the Pool

Many pool owners find it easier to pour the chlorine directly into the pool. This method is highly convenient for liquid chlorine as you only need to pour it into the pool and run the pump to circulate it all around the pool.

You can also use this method for powder and tablet chlorine, but you first need to dissolve them in a bucket of water.

Method 2: Use a Chlorine Dispenser

Automatic floating chlorine dispensers like the AquaAce Pool Chlorine Floater Dispenser are ideal when using chlorine tablets. These little chlorine pucks will float around the pool and slowly dissolve and release small doses of chlorine into the pool water.

Chlorine dispensers are cheap, but they often get stuck behind ladders and are not always very effective at chlorinating larger pools.

Method 3: Add Chlorine to a Skimmer Basket

You can also pour the chlorine into the pool’s skimmer and allow your water filtration system to circulate it around the pool.

This method works very well for tablet chlorine, but it is essential not to leave any chlorine in the skimmer when the pump is off as this can corrode it and other nearby fixtures.

Method 4: Use an Automatic Chlorinator

An automatic chlorinator is a small fixture that will attach to a pool’s filter system and add a pre-set dose of chlorine to the pool water. A pool owner only needs to ensure the chlorinator has enough chlorine (preferably tablets) and choose the amount of chlorine to add using a dial.

Automatic chlorinators allow you to control chlorine levels in the pool more precisely or add large amounts to shock the pool. They are a little pricier compared to other methods, but they are worth every buck.

The Hayward CL200 In-line Automatic Chemical Feeder is an excellent automatic chlorinator model as it is also quite affordable.

Read more: How to Lower Chlorine in Pool


Chlorine is an essential compound for cleaning and sanitizing your pool. It is vital to know what it is all about to ensure you get the best from it as a pool owner.

Also, it is vital to remember that chlorine is a corrosive chemical that requires proper handling by wearing protective gear. Lastly, also make sure you constantly monitor chlorine levels to ensure your pool remains clean and sanitized.

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