Do saltwater hot tubs use chlorine?
Yes. A salt system uses electricity to make chlorine from salt, a process called electrolysis, so the water still holds chlorine. In the One Model, the salt system makes it, and you still test the water with a strip each week.
How does a saltwater hot tub make chlorine?
A salt system takes salt and uses electricity to turn it into chlorine. The process is called electrolysis. The part that does the work is the salt cell, and it wears out over time. In the One Model, the salt cell is replaced every 6 to 18 months.
The result is chlorine in the water, made inside the tub instead of bought and poured in. The CDC says chlorine is added to hot tub water to kill germs, and that it does not work right away. A salt system makes that chlorine inside the tub.
What is the difference between salt water and chlorine?
The difference is where the chlorine comes from. In a regular hot tub, the owner buys chlorine, measures it and pours it in by hand. In a saltwater tub, the system makes it.
The water still holds chlorine, so the usual rules apply. The CDC recommends at least 3 ppm of chlorine in a hot tub and a pH of 7.0 to 7.8. It says high pH weakens chlorine, and low pH can corrode pipes. This is why a saltwater tub still gets tested.
How does saltwater compare with bromine?
Bromine is another sanitiser. The King County public health hot tub guide (Seattle and King County, Washington) describes it as related to chlorine and says it works in a similar way. It combines with organic matter in the water to form bromamines, which do not smell the way chloramines do, and which still help disinfect.
The King County guide says to measure the bromine level. The One Model makes chlorine from salt.
What are the pros and cons of a saltwater hot tub?
On the plus side, the tub makes its own chlorine, so there are far fewer chemicals to buy and handle.
On the other side, there are still jobs. You test the water with a strip each week and check the salt system's run time, which is about 8 hours a day by default and can be changed to match how much you use the tub. The salt cell has to be replaced every 6 to 18 months, and its price is not set yet. The salt system also needs electricity to do its work.
A saltwater tub still has chlorine in it, and it can still need a pH adjuster.
How does the One Model handle saltwater and chlorine?
The salt system makes chlorine from salt. Alongside it, a ClearCore ozone chamber breaks down contaminants as the water passes through, Active Skim pulls leaves, hair and oils off the surface, and an antimicrobial filter traps dirt and debris. All of it works on the water pump, which runs 24 hours a day.
Waterlab sits in the plumbing and reads pH, ORP and temperature. ORP is a measure of how well the sanitiser is working. The app (Gecko in.touch 3) shows the readings on your phone and tells you what the water needs. Good Hot Tubs describes this as minimum chemistry.
What does a saltwater tub still need from you?
Once a week, test the water with a strip, enter the result in the app and check the salt system's run time. Every 3 to 6 months, check the filter and replace it. Every 6 to 18 months, replace the salt cell. Once a year, book a check-up with your local expert. Every 1 to 2 years, drain and refill.
Ozone does not replace chlorine. The King County guide says ozone kills on contact and leaves nothing behind, so a tub still needs a sanitiser in the water at all times. That is the job the salt system does in the One Model.
On Vancouver Island, a local expert looks after the tub, and a One Model is set up and running for test soaks. If you want to see where the salt system sits in the plumbing, ask on the day.
Before ordering, the team looks at your yard on a video call, and a local expert on Vancouver Island delivers and sets up the tub. Ask about the salt system and the weekly routine then.
Questions
Does a saltwater hot tub still need chemicals?
Yes, a few common ones. You lower pH with cleaning vinegar and raise alkalinity with baking soda, and liquid chlorine can be used to shock the water. The tub starts on sea salt or a pool salt blend and makes its own chlorine, so there are no specialty chemicals to buy.
How long does a saltwater hot tub salt cell last?
In the One Model, the salt cell is replaced every 6 to 18 months.
Is a saltwater hot tub better than a chlorine hot tub?
Both end up with chlorine in the water. The difference is that a saltwater tub makes the chlorine itself, so you buy and handle fewer chemicals.
Do you still test a saltwater hot tub?
Yes. The One Model owner tests with a strip once a week and enters the result in the app. The CDC says owners must routinely test chlorine and pH.
Sources
General facts on this page come from these public sources. Facts about the One Model come from Good Hot Tubs.
- Home Pool and Hot Tub Water Treatment and Testing. U.S. Centers for Disease Control and Prevention (CDC).
- Staying Happy and Healthy in Your Hot Tub, sixth edition (PDF). Public Health, Seattle and King County.
Related answers
Is the One Model right for you?
Ten questions about your home and how you would use a hot tub. You see your result before you give any contact details, and you can ask for a test soak on Vancouver Island when you send it.