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Total Chlorine Vs. Free Chlorine What’s The Difference

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Chlorine is an optimal chemical substance which is commonly used all across the word with all clean drinking water. The reason behind this is, it has the ultimate range of disinfecting and bleaching ability.

It is widely used in various industries and household works like maintaining a clean swimming pool. At the early period of installation your swimming pool company will guide you how to choose them and how to use them accordingly.

This extreme sanitizer is available in various forms. For keeping your swimming pool water quality at premium level you should check your pool water for both total chlorine and free chlorine. 

What is the role of chlorine at your pool water? – Sanitization

Chlorine sanitizes your swimming pool water while you add them at the right time with the right amount. When the free chlorine is mixed in the water it converts into hypochlorous acid, this fight against disease causing microbes.

If chlorine interacts with swimmers’ body fluid or sunscreen, it forms chloramines, which is also known as combined chlorine. This leaves your pool throughout-gassing.

Why is chlorine effective for pool water sanitization?

The elements in chlorine breakdown once it is introduced with the pool water into hypochlorite ion and hypochlorous acid. These are the capable killers of bacteria and other microorganisms in the pool water.

The undesired compounds like ammonia or bacteria will be oxidized when it makes contact with chlorine this will make them harmless.

Make sure you always produce the right amount of chlorine into your swimming pool while sanitizing and knowing their importance as well as their problem will do a better part for regular maintenance, because chlorine is a strong chemical, if it exceeds, it will cause an itchy skin.

What causes the irritating chlorine smell in the swimming pool?

The irritating smell of chlorine is due to the formation of chloramines. This smell is a sign of pool water quality management. The routine monitoring combined, total, and free chlorine range will assist to avoid or remove issues caused by poor water quality before it becomes a big problem. 

Free Chlorine

The amount of chlorine in a swimming pool water is known as free chlorine, it is measured in parts per million (ppm), which is utilized for elimination of disease causing microbes and nullifying foreign particles.

This calculated range of chlorine is still not reacted with microbes or chemicals in the swimming pool water. Testing this free chlorine is a tough job in pool maintenance to prevent any harmful foreign particles.

Combined Chlorine

While sanitization happens the free chlorine binds with contaminants and forms combined chlorine.

If the combined chlorine is detected in your swimming pool water, there is nullification of contaminants going on. Zero amount of combined chlorine is the sign of clean swimming pool water. The regular monitor of free chlorine amounts in your swimming pool water will highly reduce the combined chlorine levels.

Total Chlorine

The total amount of free chlorine and combined chlorine is known as total chlorine. In mathematical terms, the sum of free chlorine and combined chlorine is equal to total chlorine.

Some cheap tests only indicated the total chlorine amount only. There is zero amount of combined chlorine in chlorinated clean water hence the total chlorine in this sanitized water is similar to the free chlorine.

Unfortunately, without an individual testing method for free chlorine, confirmation of zero combined chlorine is hard.

So you should test both free chlorine and total chlorine range individually. Later you can minus the free chlorine from the total chlorine to know the level of combined chlorine. In mathematical terms, subtraction of free chlorine from total chlorine will be the level of combined chlorine.

Tests for Free, combined, and total chlorine in pool water

There are three tests available to test the level of Free, combined, and total chlorine in pool water. They are: classic method of test strips, a chlorine test kit, or an advanced digital chlorine sensor.

  • Litmus style chlorine test strips, indicates the approximate level of free, combined, and total chlorine by changing its color when it interacts with water.
  • Chlorine test kit needs water sample from pool, in this sample water add the given chemical reagent. This will lead to color change in sample water depending on the amount of free, combined, and total chlorine present in the sample pool water.
  • An advanced digital chlorine detector is well known for its accuracy. This will hand over the actual level of free, combined, and total chlorine in your pool water. It doesn’t require sample water or color comparison method to know the values. The digital meter will deliver the accurate values of the free, combined, and total chlorine level in ppm instantly. 

What are the safe chlorine levels for pool water?

The proper maintenance of chlorine in your pool water is a promise for clean and safe water without chloramines. Chlorine tests will provide the level of chlorine; however, a swimmer can feel the chlorine level. If the chlorine smell is obvious or any irritation around sensitive areas like the eye or limbs are the sign of poor free chlorine level. Don’t let the swimmers inside the pool if the chlorine level is poor until the optimal level is detected after chlorine proper treatment.

  • The ideal range for Free chlorine is 2.0 to 4.0 ppm and the safe range is 1.0 to 6.0 ppm
  • The ideal range for Combined chlorine is less than 0.2 ppm and the safe range is 0.5 ppm
  • The range of Total chlorine should be similar to free chlorine often.


Proper maintenance of your swimming pool will help you to maintain a good relationship with your pool. When you find anything abnormal in it like chlorine smell or skin itching, instantly perform the chlorine test.

If it is out numbered from the preferred level treat your pool water with the right amount of chlorine.  Rebalancing the chlorine level also helps you to sanitize your pool water before any problem arises. 

If the chlorine level exceeds the right level, don’t go swimming at least for a day, just simply avoid making contact with your pool water. The range will gradually come to normal after some time. 

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