Free Chlorine Target Range: 1.0-3.0 ppm

When it comes to maintaining your swimming pool and keeping your water balanced no chemical is more important than chlorine.

Chlorine is the chemical compound that works to kill contaminants in your pool water like bacteria, sweat, urine, skin oils, and other microorganisms that could otherwise cause harm.

Chlorine is classified into three main categories that every pool owner should be familiar with: Free Chlorine, Combined Chlorine, and Total Chlorine.  Each type of chlorine measures the effectiveness of sanitization and understanding each of them will help you maintain clean and clear water.

To know the differences between free, combined, and total chlorine, let’s take a look at this simple formula:

Free Chlorine + Combined Chlorine = Total Chlorine


Free Chlorine
The easiest way to understand free chlorine is to consider the phrase itself “free chlorine.”  Free Chlorine is the unused chlorine that’s still free, active, and available to sanitize your water. It’s essential to keep it in a range between 1.0 - 3.0 ppm.

Combined Chlorine
When available chlorine comes into contact with contaminants like skin oils, urine, sweat, etc. they react to form combined chlorine, also known as chloramines.

Chloramines represent one thing: used up chlorine, or combined chlorine and is also the source of that “bad” chlorine smell, as well as the red eyes, and itchy skin.

 Once combined chlorine is formed its ability to disinfect is significantly limited. In short, combined chlorine is chlorine that’s already been used for sanitization.

Total Chlorine
Total chlorine is the sum of the free chlorine and combined chlorine in your pool water.  In typical operation total chlorine can be used as if it were free chlorine because combined chlorine is usually zero. But it’s when you have algae or some other problems going on that the total chlorine levels are useless without knowledge of the free chlorine.

Hopefully, now you have a better understanding of what the differences are between free, combined, and total chlorine. This should help you make sure the chlorine is helping your pool and protecting your friends and family from harmful chloramines.

Having problems balancing and maintaining your pool water?  NO PROBLEM! Bring your water sample into one of our stores & let our chemical experts test it for free!