Chlorine vs. Bleach for Pools: What is the Difference?

Chlorine vs. Bleach for Pools

Keeping your pools clean is always a daunting task as you have to fight both elements and all kinds of contaminants from the environment and swimmers. However, the battle is often winnable with the right products.

Chlorine and bleach are two of the most common pool disinfectants. While many swimming pool owners use them almost interchangeably, they are not the same.

Both can still do a good job cleaning your pool water, but it is important to know how they differ, their similarities, and which one to use depending on your specific situation.

What is Chlorine? 

Pool chlorine will consist of at least 65% calcium hypochlorite, and the rest is calcium and a few other inert compounds. The compound is made primarily for disinfecting swimming pools and other things like hot tubs and spas.

You can get pool chlorine in liquid, powder, tablet, or granular form. When you add chlorine to the pool water, it breaks down into several compounds. But what cleans the water is hypochlorous acid (HOCl) and the hypochlorite ions (OCl-).

These compounds will kill the bacteria by attacking their cell walls and destroying their internal structure, which oxides and makes them harmless.

What is Bleach? 

The bleach that many pool owners use to sanitize their swimming pools typically has the same properties as regular household bleach (sodium hypochlorite NaOCl).

It has around 6% chlorine, and it will also include sodium hypochlorite, salt to keep the chlorine in liquid form, and some water.

Like pool chlorine, bleach will use hypochlorous acid to attack the cell wall of the contaminants, oxidize and render them harmless.

Besides killing germs, the hypochlorous acid produced by the bleach also makes other types of contaminants like bacteria inert.

Similarities Between Chlorine and Bleach 

The main similarity between these two pool cleaning agents is their composition, as they will include the same compounds. These similar compounds include chlorine and hypochlorous acid, but they are in varying proportions.

Additionally, the two also have the same active ingredient; sodium hypochlorite. Hence, they are basically the same water disinfecting compound, except that the bleach is typically highly diluted.

Difference Between Chlorine and Bleach 

1. Free Available Chlorine: Although both chlorine and bleach end up forming the same compound when cleaning water, their effectiveness differs significantly as the amount of free available chlorine (FAC) is not the same.

If you dissolve a gram of chorine in a liter of water, you will get around 0.47 FAC level. However, if you dissolve the same quantity of bleach in a liter of water, you only get about 0.04 FAC level.

2: Form: Chlorine is a naturally occurring substance that you can get in various forms. You can get it in liquid, tablet, granular, and even powder form, and all are available for use on your pool. On the other hand, bleach is only available in liquid form.

3. Cost: Pool chlorine is way more expensive than bleach. On average, you can expect to spend at least $5 per pound of powder tablet or granular chlorine, while a gallon of liquid chlorine costs over $30.

A gallon of bleach hardly ever costs more than $3, which means a pound will cost you about $0.35. Even if you have to use ten times more bleach than chlorine, it will still save you more money.

4. Convenience: Bleach seems more convenient as you can quickly pour it directly into the pool’s skimmer, but the same is true for liquid chlorine. Other forms of chlorine will require dilution before use, which means extra work for you.

But, also note that when using bleach, you may need to add several bottles, which can be an inconvenience. Hence, here it is all up to you to decide what you find most convenient.


Chlorine and bleach are both effective pool cleaning and sanitizing agents. However, chlorine is a more potent option that will do a much better job cleaning your pool water.

That said, bleach is a more affordable solution no matter how much of it you will need to use. Hence, if you are looking for a budget-friendly solution, it can be handy for you.

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