Can You Use Saltwater for a Hot Tub?

close up of hot tubs jets underwater

When it comes to hot tubs, the traditional method for keeping tub water clean and clear has been through the use of chemicals like chlorine and bromine. In recent years, an alternative method has gained popularity: saltwater hot tubs that instead use salt as the water sanitizer. Most hot tubs are not designed for saltwater use, however almost any hot tub can be converted into a salt water one by adding a salt chlorine generator.

What is a Saltwater Hot Tub?

Most hot tubs are not designed for saltwater use, so you shouldn’t put salt in a hot tub unless it’s designed to handle it. Saltwater systems work by generating natural chlorine from salt. The system consists of a salt cell, and when an electric current is passed through the cell, the salt in the water is converted into hypochlorous acid, which is a natural form of chlorine. This process, known as electrolysis, releases chlorine into the water, where it acts as a sanitizer. The tub water is still sanitized with chlorine, but you no longer need to add it to the water, as the chlorinator slowly and systematically breaks down salt to create a constant and balanced supply of sanitizing chlorine.

Conventional hot tubs require you to add chlorine or bromine to your tub to keep the water clean, safe and fresh. With a salt water hot tub, you’ll add salt into the water rather than chlorine or bromine. Salt water hot tubs use a specialized type of salt that’s chemically the same as table salt but much coarser than the food additive. The concentration of salt is typically 3,000 to 5,000 parts per million (ppm), which is much lower than the salt level in seawater. Salt is added to the hot tub as needed and doesn’t need to be replenished very often, as it doesn’t evaporate with the water.

Before you can convert to a salt water hot tub, you need to decide what kind of salt water chlorinator you want to use: an in-line system or drop-in. The easiest way to convert to a salt water tub is with a drop-in chlorinator. No permanent alterations are necessary for its quick installation, but you will have a thin cord connected to the chlorinator cell that hangs over the side of your tub. An in-line salt water conversion kit is spliced directly into the plumbing, so the cell becomes part of the spa’s circulation system, so you’ll need to hire a plumber. These kits may void your warranty, so check with your spa manufacturer before installing one.

Is a Salt Water Tub Worth It?

A salt water system is designed to create a constant supply of chlorine from the interaction of salt and water through electrolysis. The small amount of chlorine produced by this process is enough to keep water contaminant-free, while limiting exposure to chloramines which can be helpful for sensitive individuals. While you don’t need to add chlorine or bromine to a salt water hot tub, the end result is still water that contains these chemicals, and you’ll also need non-chlorine shock and balancing chemicals, such as pH increaser or pH decreaser, to keep your water chemistry balanced.

All hot tubs require maintenance, no matter what you use to sanitize them. Traditional hot tub water care systems involve regular testing and monitoring to make sure pH levels are correct and chemicals are properly balanced, and a salt water hot tub can be just as complicated to maintain. Salt water spas have a steady concentration of sanitizer being added all the time, so the water may need to be replaced less frequently and the overall hot tub water chemistry may need less adjusting, but regular water care, like testing and balancing pH, is still required.

Salt water hot tub systems cost more to purchase and install than traditional water care systems, and while this cost is potentially offset by less ongoing costs of water care supplies and test kits, you will spend more up front, and after a few years of use the salt water cell that powers the purification process will need to be replaced. While salt is corrosive, corrosion isn’t a serious concern because the level of salt is so low, and most tubs are made primarily of non-corrosive materials like molded acrylic. However, there’s a slightly increased risk of damage to certain parts like rubber seals or metal fixtures, from constant exposure to salt water.

If you’re having trouble deciding whether to use a saltwater system or a traditional chlorine system in your new spa, our team of friendly, experienced staff can help you navigate the best choice. Give us a call at 970-879-4390 or contact us here