Struggling to keep your swim spa water clean and clear? You’re not alone. The biggest question for swim spa owners (and retailers) is:

What do you use to sanitize a swim spa?

Answer: Products made to sanitize hot tubs or pools.

These products will work, however, these sanitizing products are made for the smaller, consistently hotter waters of hot tubs or the larger, cooler water in pools. Plus, dosing directions are unclear, confusing, and not specified for swim spas.

Most important, most swim spa manuals list products that will void their warranty – users must read their manuals carefully to avoid damaging their swim spa and protect their investment.

Of course, sanitizing swim spa water is essential, and products available will work in a swim spa.

But once you purchase a product and bring it home to use, you’ll encounter “Directions for Use.”

Consider these 3 examples for products now on store shelves:

We know, reading directions is not fun, but power through reading these, we’ll explain! These examples are verbatim from labels; brand and product names are not used to protect their identity.

This is where it gets tricky.

Product #1 Granulated Chlorine: For Spas and Hot Tubs

A small stack of granulated chlorine
MAINTENANCE DOSES: With pump on add ½ teaspoon of this product per 100 gallons of water (or 5 teaspoons per 1,000 gallons of water). Repeat at 15 to 20 minute intervals until a residual of 3-5 ppm of available chlorine is established as determined by a test kit. A test kit must be used regularly to determine the frequency of additional doses of this product needed to maintain the residual of 3-5 ppm.
A silver tablespoon of chlorinating granules

Product #2 Chlorinating Granules: DIRECTIONS FOR USE

With circulation pump on add 1 tablespoon or ½ ounce of this product for every 500 gallons of water. Regular additions will be necessary to maintain 2-4 ppm of free available chlorine at all times. Actual dosage of product required to maintain the desired residual of chlorine may vary with spa use and water temperature. Use a test kit regularly to maintain the proper free chlorine.

Product #3 Chlorinating Granules: DIRECTIONS FOR USE

(Note, this is on a black label with the words in light gray, in small type like this:

REGULAR USE: Turn on the circulation system and ensure that is it operating properly. Sprinkle approximately 3 teaspoons per 500 gallons of this product over the surface of the water. Always use a clean, dry spoon. Test for FAC and add additional product if to attain 4-5 ppm FAC. Maintain 1-3 ppm FAC while the spa or hot tub is in use. After each use shock treat with 9 teaspoons per 500 gallons of water to control odors and algae. Repeat as needed. Re-entry into spas is prohibited above levels of 3 ppm of chlorine.

If you own a swim spa, it’s very likely that the sanitizing product you’re using has directions similar to these.

What’s wrong with these “Directions for Use?”

1. You have to do the math.

Some, but not all, people like math. True, your mobile device probably has a calculator  – or you could just ask Siri or Google for help.

A red pencil jots down math equations on college ruled paper

However, it’s important to be accurate when you add chlorine. Too little and your water is not properly sanitized, putting all users at risk. Too much makes water harsh, fades swimsuits, irritates skin, and is harmful to surfaces.

Goldilocks wasn’t wrong when she wanted everything to be “just right.”

Various silver measuring spoons sit on a grey background

2. You have to find a tablespoon, a teaspoon, or a scale – and a clean one.

If you have teenagers in your home, finding a clean spoon can be a challenge. And chances are, when you find one, it may belong to one of your kids’ friends (you should return it).

Once found, you need to ensure that the teaspoon or tablespoon used to measure and sprinkle chlorine is not available for the dog to lick or younger children to put in their mouths. That’s a warning, printed on all product labels – you’re using harsh chemicals.

3. Confusing Directions

And when you read these directions, “A test kit must be used regularly to determine the frequency of additional doses of this product needed to maintain the residual of 3-5 ppm.”

You may have a few questions like:

What test kit should I use? Does that include a test strip? Or do I need a kit?

What is “regularly?” Once a week? Every other day?

How many “additional doses” do you put in?

Is maintaining 5 ppm of chlorine good for your swim spa, your swimsuits, skin and surfaces?

What is a “residual?”

Is that before you get into the swim spa?

While you’re using the swim spa?

After everyone is out of the swim spa?

The period of time when no one is using the swim spa?

And what does this mean: “Actual dosage of product required to maintain the desired residual of chlorine may vary with spa use and water temperature.”

It probably means if you use the spa a lot, you may need more product. If the water is hotter, you may need to use more products. If the water is colder, you would use less products.

And it may mean you need to keep adding chlorine until you use a test kit or test strip to measure the “desired residual of chlorine.”

And one last question:

“Test for FAC and add additional product if necessary to attain 4-5 ppm FAC. Maintain 1-3 ppm FAC while the spa or hot tub is in use. After each use shock treat with 9 teaspoons per 500 gallons of water to control odors and algae. Repeat as needed. Re-entry into spas is prohibited above levels of 3 ppm of chlorine.”

What is FAC? It’s true, people use acronyms routinely in their workplaces and in community organizations. However, FAC is probably not a commonly used acronym around the neighborhood.

FAC is “free available chlorine.” It’s chlorine that is ready to protect your water vs chlorine that has bound up with stuff in the water and is no longer effective.

Also, it says you need to “attain 4-5 ppm of FAC.” But “Maintain 1-3 ppm of FAC while the spa or hot tub is in use.” Does that mean you keep it at 4-5 ppm of FAC, but then, when can you get in, it needs to be 1-3 ppm of FAC while in use?

And, you are “prohibited to use the spa at levels above 3 ppm of chlorine” – is that FAC? Or total chlorine?

A photo of the shelves of sanitizing products at a local dealer

We’re not making fun of these products

These are real examples, taken from product labels on the products you’ll find on the shelf at the pool and hot tub store and/or online.

They may sound funny, however, these are a few of the real, honest questions people who buy and use these products may have.

These are not unsurmountable questions. Many people are using these products in their swim spas and are satisfied with them.

Plus, they know that pool and hot tub retailers are ready to answer questions and help them.

Perhaps because directions are unclear and confusing (and people generally don’t read directions), they just add a capful every time they use the swim spa.

And then they are surprised when the water is cloudy – or worse, green. Or it’s harsh and irritable, or smelly. They don’t know what to do.

The fact is, water care can be challenging. Water balance in one key part of water care. Balancing the water and keeping it balanced can be especially challenging because of the many factors involved.

Most people don’t want to become backyard chemists to have a clean, clear swim spa; they want to use it for exercise, fun, or relaxing.

A photo of FROG @ease for Swim Spas that sits on a swim spas edge next to 3 rolled up white towels

Good news: there is now an easier way to keep your swim spa water clean and clear

FROG® @ease® Sanitizing System for Swim Spas is the first and only complete sanitizing system purpose-built for the volume, temperatures and uses that are unique to swim spas.

The System comes with FROG @ease Test Strips to test the water so you can keep it within proper guidelines.

All sanitizers are most effective when water is kept within ideal parameters:

  • Total Alkalinity: 80 -120 ppm

  • pH: 7.2 – 7.6

  • Total Hardness: (or Calcium Hardness) 150 – 250 ppm

(For help with water balance – check out FROG’s Water Balance Guidelines.)

FROG @ease for Swim Spas keeps swim spa water clean and clear for up to 4 weeks, depending upon the swim spa size and how often it’s used.

Please note that whatever sanitizer you use, you’ll use more of it if you use the swim spa more often than a few times a week or many people use it. For example, if you have a party and many people are in and out of the swim spa, you’ll use a lot of sanitizer.

With “Chlorinating Granules” you’ll need to add more with each use.

Image of FROG @ease for Swim Spas in front of its packaged box

With FROG @ease for Swim Spas, you’ll use more chlorine faster with a large group of people too.

However, with regular use (usually a few times a week) you shock only once a month, and the SmartChlor® Cartridge lasts up to 4 weeks.

Plus, FROG @ease kills bacteria 2 ways, with FROG Minerals and SmartChlor, a unique, patented type of chlorine that releases slowly and maintains a continuous low 0.5 – 1.0 ppm chlorine level at all times – it self-regulates.

When more people use the swim spa, FROG @ease releases more chlorine to meet demand. And it keeps the level consistent when people are in or out of the water. FROG @ease keeps the water at a consistent chlorine level, so water stays clean, clear and ready for use.

With “Chlorinating Granules” chlorine levels spike and dip – you have to add more chlorine after each use – the directions state this. With FROG @ease for Swim Spas, chlorine levels remain consistent when you’re using the swim spa, and when no one is using the swim spa.

An overhead shot of a swim spa with FROG @ease sitting on its edge alongside 3 rolled up white towels

FROG @ease Directions for Use are Clear and Simple:

  1. Remove outer packaging from the FROG @ease Mineral Cartridge and FROG @ease SmartChlor.

  2. Align the FROG @ease SmartChlor Cartridge with tab guides on the FROG @ease Mineral Cartridge. Push together until you hear the cartridge click into place.

  3. Adjust to setting number based on swim spa gallon size (see Setting Chart). If a dual zone swim spa, set according to the gallons of the swimming area only.

  4. Attach to railing of swim spa with the tether provided and let it float in the swim spa.

FROG @ease was launched in January 2024 – it’s new on the market!

Now, to answer the question of “How do you sanitize a swim spa?”

FROG @ease for Swim Spas floats in a swim spa as a man swims in the background

The easy way – with FROG @ease for Swim Spas. Learn more about FROG @ease for Swim Spas here!

Find your local retailer on the FROG website, enter your zip code in the “Dealer Locator” in the upper right corner – you’ll see a list of retailers in your area.

If you have questions, use the chat box, “Ask FROG,” a real person will help you.


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