Free Chlorine vs Total Chlorine – What’s the Difference?

In the pool and spa industry, there are two main categories of chlorine-free chlorine and total chlorine. It’s important to know what these terms mean so that you can make an informed decision about which type of product will work best for your needs. Total Chlorine is a measurement of all the different types of compounds in a sample, while Free Chlorine is only one category within this group.

For example, if you have 100 parts per million (ppm) of total chlorine but only 10 ppm or less as free chlorine, then it may not be enough to kill off bacteria in your water and prevent algae growth on your surfaces as it should be.

Have a look at what each type of chlorine does, how they differ from each other, and which one you should use for your pool.

high chlorine in pool


Understanding Free Chlorine

Free Chlorine is a chemical used in water treatment to kill bacteria and other microorganisms. It’s also called chloramine, which is a combination of chlorine and ammonia. In order for it to work correctly, there must be enough dissolved oxygen present in the water. The amount of free chlorine you need varies depending on how often you use your pool and its type (e.g., residential or commercial).

How to measure Free Chlorine level in your swimming pool?

The Free Chlorine Level is a measure of the concentration of chlorine or another oxidizing agent in water. It is usually expressed as parts per million (ppm) or milligrams per litre (mg/L). In pools, it should be between 2-4 ppm for proper sanitation. The higher the number, the more effective it will be at keeping bacteria and algae from growing. Whereas a low reading can lead to eye irritation, skin rashes and other health issues.

If you want to know how much free chlorine is in your pool, there are two ways you can measure it – with a test kit or by using an electronic tester. You should be testing your free chlorine levels at least once per week during the swimming season (April-September). The best time to take a reading is early morning before anyone swims in the pool for 24 hours. This will give you accurate results of what’s happening with your water chemistry throughout the day.

chlorine too high in pool

To maintain these levels, check them every day when you open your pool and adjust accordingly as needed based on what you find out from testing!

Utility of free chlorine

Free chlorine plays a crucial role in the safety and well-being of swimmers. It’s essential to keep your free chlorine levels balanced enough so that they can kill any bacteria or algae before they have time to grow into more significant problems like skin irritation, eye irritation and respiratory issues.

If it gets too low, there’s a risk that harmful organisms will grow in the water. Too high, and you’ll have an unpleasant smell from chloramines (chlorine combined with sweat or urine). Therefore, you need to maintain the balance.
It also works to prevent algae growth by breaking down organic matter into harmless compounds.
It is also used for disinfecting water, swimming pools, spas, hot tubs, and other recreational water facilities. When combined with other chemicals, it can also be used as a bleaching agent for laundry or industrial processes such as pulp and paper production.

Understanding Total Chlorine

Before understanding the concept of total chlorine, you need to be well-versed with the term “combined chlorine”. Combined chlorine is a water treatment chemical used in swimming pools, hot tubs and other bodies of water. It combines chlorine with another substance to create a more powerful disinfectant. This means it’s able to kill bacteria and algae faster than regular free chlorine alone.

Now, let’s get acquainted with total chlorine. The total chlorine level in the pool water is simply the sum of combined and free chlorine levels. If the free and total chlorine levels are equivalent, it means that there is no combined chlorine present in your swimming pool.

total chlorine vs free chlorine

How to measure Total Chlorine level in your swimming pool?

The Total Chlorine test is used for measuring the concentration of chlorine in a water sample. It measures the total amount of chlorine, including free and combined chlorine. This level should be between 1-4 ppm to maintain a safe and comfortable environment for swimmers.

One way to measure total chlorine level is with test strips, which can be purchased at any local hardware store or online. They’re inexpensive, accurate, and require no extra tools or training to use them properly.

Another way is with a liquid chlorine dispenser that measures the amount of chlorine being added to the water by weight. It is a good choice if you’re looking for something simple but need some help calculating how much chemical needs to be added each time based on your pool size and usage habits. They will automatically dispense just enough chemical every day without wasting any chemicals or having leftover chemicals sitting around waiting until next week’s measurement.

A third option is an electronic meter that reads and displays results on its screen. This method is preferred if you don’t mind spending more money upfront but would like more accuracy over time and less maintenance than other methods.

Why is it essential to measure the total chlorine level?

To ensure that your swimming experience is as safe and enjoyable as possible, you must know how much total chlorine is in your pool at all times. The right amount of total chlorine will help prevent algae growth, bacteria formation, and other harmful contaminants from developing in the water.

Bottom Line 

The two terms- Free Chlorine and Total Chlorine are often used interchangeably, but they have different meanings. Free chlorine refers to the amount of chlorine in a water supply that has not combined with other substances such as ammonia or organic matter. Total chlorine refers to all forms of chlorine found in a water supply, including free and combined forms. If you want your pool to be clear and sparkling clean, it’s essential to know how much free and total chlorine is present in your pool water.