Understanding Chlorine

Simply put, chlorine is what sanitizes your pool. This is the biggest help in making your pool water safe and hygienic for swimming! But what exactly does chlorine do? And why are there different kinds?

Brace yourself for some schooling, because there will be a bit of chemistry involved in this explanation! First, chlorine reacts with your pool water to form hypochlorous acid and hypochlorite ion. Combined, these compounds form “free chlorine.” You want your water’s FC level to be between one and four parts per million (ppm) so the chemical can do its job.

When the chlorine you’ve added begins to react with contaminants in the water, such as nitrogen and ammonia, you’ve not got “combined chlorine.” Combined chlorine is chlorine that has already been used. Because the combined chlorine as some contaminants in it, it is not as effective as free chlorine in sanitizing the pool. You want to keep your CC level to less than 0.2 ppm.

Remember, to ensure your pool is sanitized properly, your free chlorine should remain higher than your combined chlorine.

There is also something known as “breakpoint chlorination,” which is when you have enough FC to shatter the molecular bonds of chloramine. You need to add ten times the amount of CC to hit this point. If you’ve heard of “shocking” your pool, this is what you’re aiming for in this process. Not hitting the breakpoint can result in even more chloramines in your pool, and if the chloramine levels continue to rise unchecked, you may eventually have to partially or even fully replace your water to fix the issue.

Blue Ribbon Pools offers free water testing, where we can test the chlorine levels of your pool for you as long as you bring in a water sample. We can then recommend what you should do next. If you need help shocking your pool, understanding the chlorine levels, or would like someone to do the “dirty” work for you, contact Blue Ribbon Pools today to schedule maintenance!

(Thanks to Swim University for additional info provided for this article.)