The Argument Against Saltwater Pools

When discussing chemical treatment options for pools and spas, I’m often asked about saltwater chlorination. Many people have heard a lot of good things about it and are curious if it’s a good choice for them.

I’ll come clean right here at the start and say that I am not an advocate of this technology, although I do understand the appeal. “Saltwater pools” have been around a long time and have seen a dramatic rise and, later, fall in popularity. The technology came to the U.S. in the early 90s, originating in Australia. It caught on slowly at first, but then in the early 2000s, it seemed as though everyone wanted to transition to the method.

And make no mistake; saltwater chlorination does come with a considerable list of potential benefits. You don’t have to purchase chlorine, transport it, or store it on site. Saltwater pools gained a reputation for silky smooth water, and it is true that the electrolytic process does provide constant super-chlorination inside the salt cell itself, thus constantly breaking up chloramines a little bit at a time.

The problems I saw, however, started with the way the systems were marketed as being maintenance-free and, even more inaccurately, that they’re not using chlorine. In fact, salt pools do require tremendous levels of maintenance, and they are most definitely chlorinated; it’s just that the chlorine is added in a different way than more traditional methods, such as feeders or the bottle-at-the-end-of-the-arm method.

Giving it a Try

Still, there was a time when I did try the concept with a handful of my service accounts. It was in the practical application that the drawbacks became abundantly clear.

First, there’s the issue that you have to add hundreds of pounds of salt to a pool, based on the volume of water, and you have to continue to add salt based on splash-out or leaks. It struck me how adding all this salt is a tremendous amount of effort and expense. The wear and tear on the service vehicles hauling around that much salt added up more quickly than one might expect.

The biggest problem I found was how the method impacts water balance. Adding that much salt increased the pH so I needed to add acid to lower the pH, and that, in turn, lowers the alkalinity as well. Then we needed to add more sodium bicarbonate to bring up the alkalinity again.

As a result, I was caught in a constant yo-yo effect that aggravates water’s natural ability to scale and corrode. It was a nightmare.

A Corrosive Character

Perhaps most troubling of all, salt water is highly corrosive. The electrolytic properties of dissolved sodium chloride will destroy metal components such as light rings, handrails, and filter internals. The corrosive nature of salt water will also wreak havoc with certain cementitious or stone materials.

Not surprising, the concept has fallen out of favor with many builders and service technicians, myself included. I went from being at least open-minded about it to now being entirely opposed to using saltwater chlorination on any of our pools.