Free Chlorine vs Total Chlorine: Difference and Comparison

Understanding the distinction between free chlorine and total chlorine might be difficult. You may easily be confused between these two chlorines without understanding the concept between them.

Generally, we may know that they are used to sanitize the water from all contaminants, especially in the pool. The article will discuss the difference between free chlorine and total chlorine.

Key Takeaways

  1. Free chlorine is the amount of chlorine available to disinfect water, whereas total chlorine is the sum of free chlorine and combined chlorine.
  2. Combined chlorine forms when free chlorine reacts with contaminants, rendering it a less effective disinfectant.
  3. To maintain safe water quality, monitoring and managing free and total chlorine levels is essential.

Free Chlorine vs Total Chlorine

Free chlorine is the amount of chlorine that can be used to kill germs like harmful microbes and neutralize contaminants. It is mostly used for sanitizing a swimming pool. Total chlorine consists of free and combined chlorine and it is always more than or equal to the amount of free chlorine.

Free Chlorine vs Total Chlorine

Free chlorine is referred to as the amount of chlorine that is used to kill harmful microbes and other germs. It is also used to neutralize contaminants.


Science Quiz

Test your knowledge about topics related to science

1 / 10

A bond that occurs between nonmetals and nonmetals is called a/an _________.

2 / 10

Acid turns blue litmus paper into which color?

3 / 10

A bond that occurs between metals and nonmetals is called a/an _______________.

4 / 10

What is the other name of Newton's first law of motion?

5 / 10

Which of the gas is not known as green house gas?

6 / 10

The filament of an electric bulb is made of

7 / 10

DNA carries the instructions for an organism to grow. DNA stands for.....

8 / 10

Fermentation is the process of ______.

9 / 10

The 'photo' in photosynthesis means to do with...

10 / 10

The hardest substance available on earth is

Your score is


It is free chlorine used to kill harmful microorganisms in the swimming pool. It is the most effective type of chlorine that is actively responsible for sanitizing the pool.

Total chlorine is the grand sum of free and combined chlorine. Total chlorine can be calculated as 

      Total Chlorine (T) = F+C (free chlorine + combined chlorine)

The total chlorine amount will always equal or exceed free chlorine amounts.

Comparison Table

Parameters of ComparisonFree ChlorineTotal Chlorine
DefinitionFree chlorine is the quantity of chlorine needed to kill microorganisms that are present in the water.Total chlorine is the combination of free and combined chlorine
FormulaNo specific formulaT= F+C
ComponentsIt includes the chlorine available for the sanitization of water in a poolIt is the chlorine that may be available or not for the sanitization of water in a pool
ValueFree chlorine has a lesser value than total chlorineTotal Chlorine is superior in value as compared to free chlorine
UsageUse to kill germs and microorganismsUse to kill germs and microorganisms

What is Free Chlorine?

Free chlorine is referred to as the chlorine that is present in the water to kill some microorganisms in the pool. Interestingly, the a reduced presence of free chlorine than that of total chlorine.

Free chlorine is in the form of hypochlorite ions, dissolved chlorine gas, and hypochlorous acid.

Hypochlorous acid is used for the measurement process because it has a strong oxidizing effect and is considered to be stronger than hypochlorite ions.

Concentration in the water of a swimming pool can be measured by the presence of chlorine which is available for the purpose of sanitization of contaminants. It is viable to measure the chlorine content present in the water.

In the process of sanitization, the amount of chlorine is consumed by water in the pool. The best and easiest way to check chlorine levels in the pool is with the help of test strips. 

Another two ways of measuring free chlorine are as follows

Colourimetric Test: The method in which some specific reagents and samples are required can cause a coloured integration in the water sample.

Amperometric Test: Amperometric is a system in which a rugged chlorine sensor compensates for ph level.

What is Total Chlorine?

Total chlorine is the economically viable test used to test the presence of both free chlorine and combined chlorine in the water. Combined chlorine is regarded as the amount of chlorine that reacts with nitrogenous compounds in the water of a pool.

This chlorine does not affect the sanitization of water. Total chlorine allows the chlorine that may or may not be available for the killing of contaminants in water.

In simpler words, combined chlorine is the chlorine amount that is not present for cleaning and sanitising water.

When combined with nitrogenous compounds, we can say that the amount of chlorine makes water inaccessible for sanitization.

Organic amines and ammonia are nitrogenous compounds that are present in water. These nitrogenous compounds may be found in polluted waters.

Moreover, ammonia is added to the water for chlorination, which works as a sanitiser. Total chlorine is measured in wastewater.

Main Differences Between Free Chlorine and Total Chlorine

  1. Free chlorine is the chlorine that is present to kill microorganisms, while total chlorine is free chlorine plus the combined chlorine.
  2. Free chlorine is used for water sanitisation, whereas total chlorine refers to the quantity of chlorine that may or may not be available for sanitization purposes.
  3. Free chlorine always has a lower value, while total chlorine has a higher value.
  4. Free chlorine is checked by test strips, whereas there is a specified formula to measure total chlorine, which is total chlorine= free chlorine + combined chlorine.
  5. Free chlorine is used to sanitize the water. On the other hand, total chlorine is not used for the purpose of sanitization of the water.
One request?

I’ve put so much effort writing this blog post to provide value to you. It’ll be very helpful for me, if you consider sharing it on social media or with your friends/family. SHARING IS ♥️

Want to save this article for later? Click the heart in the bottom right corner to save to your own articles box!

Ads Blocker Image Powered by Code Help Pro

Ads Blocker Detected!!!

We have detected that you are using extensions to block ads. Please support us by disabling these ads blocker.