What's the Difference Between Saline and Chlorine Swimming Pools?

Chlorine isn't great for the environment or your eyes. Saltwater pools are a popular option. JaySi/Shutterstock

Q: This past winter, I traveled frequently for work and noticed that many of the hotels that I stayed at boasted saltwater swimming pools. Sadly, I didn’t have the chance to test the literal waters in these pools because I was in and out of the hotels rather quickly on business (poor me!). Still, I took notice. This has me thinking: My husband and I are about to open up our home pool for the summer season (lucky me!) and we’ve always used chlorine. I’ve personally never really struggled with the side effects of the stuff, but I know it can affect others severely. Plus, from what I gather, using chlorine isn’t too great for the environment. Given that our pool gets a lot of action during the summer months, should we consider switching over to saltwater?

Sabina, Bloomfield Hills, Michigan

A: Hey, Sabina,

Lucky you is right! And I’m not just referring to the fact that you have the luxury of being able to take a dip in a private swimming hole 24/7. I’m talking about the fact that chlorine doesn’t affect you as it does other people ... like me. As a former competitive swimmer and semi-frequent patron of the adult lap swim hour at my local public pool, I’ve gotten somewhat used to the bloodshot zombie eyes, the itchy skin, the dried-out hair and pungent bleachy smell that’s a side effect not of the chlorine itself but of chloramines, irritants that form when chlorine mingles with organic compounds present on the body.

In some cases, specifically in indoor pools, the presence of chlorine byproducts like chloramines can result in compromised indoor air quality and lead to asthma and other respiratory ailments. So I suspect many hotels have made the switch to saline, or saltwater, pool-cleaning systems not because of any overarching green initiatives — although that does play a big part of it — but for the health and well being of hotel guests. Because, really, there’s nothing as unsexy as a bunch of red-eyed, bikini-clad hotel guests lounging around a pool as they scratch themselves and cough.

So, should you switch to a saltwater pool-sanitation system at home? I’d say go for it, Sabina, as it’s generally considered to be better for your health and for the environment. But be prepared to dole out a bit of cash to make the switch, as saline systems aren’t cheap to install (although operating costs are generally lower). You should also be aware of some additional electricity costs and corrosion-related damages that aren’t usually associated with pools sanitized by the frequent dumping of buckets of ozone-depleting chemicals into the water.

And to get things straight, saltwater pools aren’t exactly chlorine-free, although most saline swimmers don’t experience the aforementioned unpleasant side effects common with traditional chlorine-treated pools. Saltwater pools employ a device called a chlorine generator that, through electrolysis, breaks down salt added directly to the pool water and turns it into chlorine — yep, chlorine — that’s then transformed into hypochlorous acid, the substance that actually sanitizes the water. So essentially, by adding a couple hundred pounds of regular old salt to your pool water and installing a pricey device, you’ll be “naturally” creating and recycling chlorine compounds instead of buying and handling toxic chemicals.

And another misconception about saltwater pools: They aren’t really that salty, so don’t expect an experience akin to swimming in the ocean. And you certainly shouldn’t expect to float. According to Pool Solutions, the salinity of ocean water is about 35,000 parts per million (ppm) while most saltwater chlorine generators require 3,000 to 4,000 ppm to operate efficiently. With 9,000 ppm, human tears are even saltier than saline pools. So, yes, those who are on low-sodium diets can safely swim in a saline pool.

There’s a ton of info out there about saltwater pools, but if I were you, I’d start by asking around to see if you have any friends or neighbors who produce their own chlorine instead of adding it to the pool water. What advantages and disadvantages have they noticed?

And if you’re interested in going truly chlorine-free, I’d look into a chem-free swimming pool sanitation system like an ozone generator. Or, you could rip out your existing pool and build a popular-in-Europe natural swimming pool — a pool/pond hybrid that incorporates water-purifying aquatic plants — from scratch.

If you do end up installing a saltwater chlorine generator, let me know how it works out for you. I’ve swum in a few saline pools recently and enjoyed them.

Happy swimming!

— Matt