How to: Swim spa chemicals for beginners 

swim spa chemicals

Swim spas resemble very large hot tubs but can be enjoyed like a pool. But how do you take care of a swim spa? Is it like a hot tub — or a pool? While swim spas are unique, the way to maintain the chemicals is not all that different than a hot tub.

Maintaining the water quality is essential to safely enjoying your swim spa. With proper care, you can expect your swim spa to last up to 20 years.

This simple guide will help you understand swim spa chemicals, from start-up throughout the ownership process. And we promise — a chemistry degree is not required. 

swim spa chemical tips
You can reduce the amount of chemicals that you need for your swim spa by rinsing off before you get in the water.

Tips for clear swim spa water 

You want to spend your time enjoying your swim spa — not taking care of it. There are steps you can take, though, to avoid common water problems like cloudy water.

The most important swim spa water tip is to remember that what you bring into the spa will affect the chemical balance. What does that mean? When you use body care products, like lotion or sunscreen, they can cause the water to become cloudy. 

Important guidelines to follow:

  • Do not wear body lotion or oils in the swim spa
  • Rinse off before getting in the swim spa
  • Rinse and dry swimsuits by hand
  • Keep the the swim spa covered when you are not using it
hot tub chlorine
Chlorine is among the chemicals that you will need to add to your swim spa water to keep it clean.

Swim spa chemicals

The water of your swim spa should be treated more like a hot tub than a pool. Why? A swim spa has fewer gallons of water and is often kept at a higher temperature. While the same amount of people might use the swim spa versus a pool, the bather to water ratio is much more like a hot tub. Plus, there are jets for relaxation and swimming.

To keep your water clean and safe, you need to keep spa chemicals at home and follow a water care schedule.

Chlorine or bromine granules: Depending on your swim spa and the manufacturer’s recommendations, you will use chlorine or bromine to sanitize your water.  

Non-chlorine shock: This oxidizing agent helps break down total chlorine in your water.

pH decreaser and increaser: The pH of your swim spa water needs to be neutral for safe swimming, exercising, and relaxing. Swim spa owners might have to balance the pH. If it’s too high, above 7.6, you will use a pH decreaser. If your pH is below the recommended range, you will use a pH increaser to balance the water.

It’s important to look at the label of your swim spa chemicals. Some pH products will also balance the total alkalinity of your water while others will not. You might need to purchase separate products to increase (or decrease) the total alkalinity of your water.

Other spa chemicals and products that you want to have on hand include filter cleaner, spa defoamer, clarifier, sequestering agent, and scale remover.

how to drain a hot tub
How often should you drain and refill your swim spa? Many manufacturers recommend that you change the spa water every six months.

Routine spa water care 

Before getting in the water

Test the water of your spa to check the pH and chlorine levels. What are the proper levels? Your pH should be between 7.4 and 7.6. Your free chlorine should be between 2 and 4 ppm. If you need to balance the water, start with alkalinity. Once the alkalinity is in range, balance pH and then adjust the chlorine.

When should you not get in the water? If the water is cloudy, if the total chlorine is above 5 ppm, or there is no chlorine reading.

When you get out of the water

Anytime someone gets in the spa, the chlorine present in the water will have to “work harder” to keep the water clean. The best practice is to test the water and balance as necessary. If anything, you should add chlorine to the water. Allow the jets to run for 15 to 20 minutes and keep the cover off. 

Three times a week 

Test the water and balance the alkalinity, pH, and chlorine levels as required. 


Clean your filters by soaking them in a filter cleaner. Be sure to check the owner’s manual for your swim spa and follow the recommendations.

Most asked questions about swim spa chemicals 

How does the water temperature affect the chemicals?

The warmer the water, the more chemicals that you will need. If you are keeping your swim spa at a higher temperature, the water will require more products.

How do I get my free chlorine in the proper range? 

If you are struggling with getting your chlorine in the right range, you need to start with the total alkalinity and pH. You will never get your chlorine in the right range if the TA and pH is out of balance. Add chlorine to the water slowly, every few hours, until it’s in the proper range. 

Another factor to consider is the total chlorine level. If your total chlorine is too high, you might need to add a non-chlorinated shocking agent. Once the total chlorine has been “broken up,” you will have an easier time bringing up the free chlorine.

How often should I drain and refill my swim spa?

Spa owners should expect to change out the water every six months or so. But how often you use your spa and how many people use it. The more often you use it and the more people who are in the spa, the more frequently you might have to change the water. 

I have a dual-zone swim spa. How do I add chemicals?

A dual-zone spa means that there’s two bodies of water. There’s a hot tub and a swimming side. Each area of the spa has different pumps and topside controls, which means the chemistry of each side will differ. You will need to add chemicals to both sides of your dual-zone swim spa. Follow the water care routine for both areas to get the most out of your swim spa investment.