Is Adding Salt to a Swimming Pool The Same as Adding Chlorine?

In Blog, Salt by Cathy Erntson

There is a nagging myth in aquatics that seems to persist no matter how much information is out there. You may have come across someone with this misconception: That adding salt to a pool is adding chlorine. I have seen a site add a bag of salt because they “needed to bring their chlorine up”….cue the head shaking and sighing.

Traditional table salt is made-up of sodium and chlorine, an ionic compound that’s bonded on a one to one level. So, every molecule contains one sodium ion and one chlorine ion. Water is a polar molecule, so while it is neither positively nor negatively charged, the shape of the molecule gives it a more positive side and a more negative end, each of which attracts its opposite out of the salt giving you aqueous Na+ and Cl-. Sounds like you have chlorinated water, right? Let’s look at combined chlorine. They contain chlorine yet do not produce a sanitizing effect in the water. So the aqueous Cl- that you get from dissolving the salt in water is similar in the sense that the chlorine is not in a form where sanitation will take place.

When we add a generator system into the mix, it changes what’s going on behind the scenes in your water. A generator system is basically 2 parts, a power source usually hanging on the wall and the actual generating cell plumbed inline. The cell contains plates of a metal (titanium) that have been coated with another metal (ruthenium or iridium). Once power is applied and electricity starts bouncing between the plates, the ensuing reaction creates Cl2, H2, and NaOH. In a nutshell, chlorine gas, hydrogen gas, and sodium hydroxide. From there, the Cl2 reacts exactly as we would expect a sanitizer to act, forming the Hypochlorous acid that makes all the sanitary action happen.

Chlorine comes in many many forms. We would all be a little wiser to remember they’re not all the same!