Tech Explained: CLEARRAY Active Oxygen (UV-C + Ozone)

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How Sundance’s Standard Water Treatment System Actually Works—Why Ozone and UV-C Together Beat Either One Alone, the Five-Step Cycle, What ‘Active Oxygen’ Really Means, What the System Does and Doesn’t Do, and the Ownership Routine

By Leisure Time Inc.  |  October 2026  |  Estimated Read Time: 13 minutes

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Every Sundance® spa we sell has a small, quiet system hidden in its equipment bay that most owners never think about—until they notice how little chlorine they’re using. That system is CLEARRAY® Active Oxygen®, and it’s the reason Sundance can describe its water care as ‘hands-free.’ It’s also one of the most misunderstood technologies in the hot tub world: people hear ‘UV’ or ‘ozone’ and assume it replaces sanitizer, or they assume it’s just an ozonator with a fancy name. Neither is right.

This is the Tech Explained version—drawn from Sundance’s own technical documentation and our experience servicing these systems across southern Idaho. We’ll cover what ozone does, what UV-C does, why putting them together produces something neither does alone (that’s the ‘active oxygen’), the five-step cycle water takes through the system, where it fits with Sundance’s filtration, what it does and doesn’t do, your sanitizer options, the ownership routine, and the basics of keeping it running.

From Leisure Time Inc., an authorized Sundance dealer with showrooms in Boise, Idaho Falls, and Twin Falls. If you own a Sundance or are shopping for one, this is the explainer that makes the rest of your water care make sense.

The Short Version

• CLEARRAY is an oxidizer, not a sanitizer. It destroys contaminants as water circulates so your sanitizer has far less to do—but you still keep a small residual of chlorine, bromine, or FROG® @ease® in the water.
• It’s two technologies working in sequence. A low dose of ozone is injected first; the water then passes a UV-C lamp, which energizes the ozonated water and unlocks ‘active oxygen’—an advanced oxidation process more powerful than ozone or UV alone.
• It treats 99.9% of waterborne pathogens (up to 99.99%, per Sundance) and reduces the need for harsh chemicals.
• It’s standard on every Sundance acrylic spa and has been factory-installed since 2012.
• It’s nearly maintenance-free: one UV-C bulb a year, and that’s about it.

Two Technologies, One System: Why Ozone and UV-C

Plenty of hot tubs have an ozonator. Some have a UV lamp. CLEARRAY has both, in a specific order, and the reason is that each one fixes the other’s weakness.

What Ozone Does

Ozone (O₃) is a highly reactive form of oxygen and a powerful oxidizer—the same technology municipal water treatment plants rely on. In the spa, it attacks organic contaminants: body oils, lotions, sweat, and the compounds that cloud water and feed bacteria. Sundance puts it simply: ozone ‘does the heavy lifting of oxidizing organic contaminants, allowing sanitizer to work for a longer period of time.’ It also reduces dissolved solids in the water. That second point matters more than it sounds, as you’ll see in a moment.

What UV-C Does

UV-C is a natural part of the sun’s spectrum, filtered out by our atmosphere, and it has a very specific effect on living things: it interacts with the DNA of bacteria and viruses and destroys their ability to reproduce. It’s the same technology used to treat bottled drinking water, aquariums, and hospital water systems. In a spa, the water passes through a chamber built from stainless steel and quartz where a UV-C lamp irradiates it. UV-C adds no chemical byproduct to the water—it’s purely light.

Why Together Is Better Than Either

UV-C has one limitation: it only works on what the light can reach. Particles and dissolved solids in the water absorb and scatter UV light, shielding microorganisms from it. That’s where the ozone step pays off twice—by oxidizing contaminants and reducing dissolved solids before the water reaches the lamp, ozone clears the way so UV-C can work at full effect. And when UV-C light hits ozonated water, something else happens: the energy breaks the ozone down into highly reactive oxygen species. That reaction is the advanced oxidation process, and the reactive molecules it produces are what Sundance calls active oxygen—stronger oxidizers than ozone itself, which ‘work harder and clean longer.’

How It Works: The Five-Step Cycle

Here’s the path water takes through CLEARRAY, as Sundance describes it. The whole cycle happens continuously inside the circulation loop, so it’s running whenever the spa is:

1. Ozone is generated and injected. A built-in ozonator produces a low-output ozone gas and injects it into the circulating water. The low output is deliberate—it minimizes off-gassing, which prolongs the life of the spa’s equipment compared with traditional, high-output ozone systems.
2. The water is mixed to saturation. A mixing process ensures the ozone fully saturates the water, where it attaches itself to microorganisms and harmful compounds.
3. The ozonated water passes the UV-C lamp. UV-C light energizes the molecules and unlocks active oxygen through the advanced oxidation process.
4. Active oxygen destroys contaminants. The reactive oxygen molecules break down contaminants and treat 99.9% of waterborne pathogens.
5. Clean water returns to the spa. Treated water is pumped back into the tub, where it keeps working on the rest of the water, breaking contaminants down into particles the filters can easily remove.

Many current models also include CLEARRAY® On-Demand, which lets you trigger an extra treatment cycle manually—useful after a big soak with a lot of people, rather than waiting for the system’s normal rhythm to catch up.

Where It Fits: The Three-Step Sundance Water System

CLEARRAY is the middle step of a three-part system, and it works best because the other two parts are strong:

The logic is clean: the skimmer and filter remove what they can catch, CLEARRAY breaks down what they can’t, and the broken-down contaminants become small enough for the filter to grab on the next pass. The sanitizer residual stands guard between soaks.

What It Does—and What It Doesn’t

This is the part that saves owners from the most common mistake.

What CLEARRAY Does

• Oxidizes organic contaminants continuously, so your sanitizer isn’t used up fighting oils and lotions.
• Treats 99.9% of waterborne pathogens as water passes through.
• Reduces the need for harsh chemicals—Jacuzzi®, Sundance’s parent, cites up to a 50% reduction in chemical dependency.
• Makes the water gentler on skin and eyes and free of the harsh chemical smell, because you’re maintaining far less sanitizer.
• Runs hands-free inside the circulation loop.

What CLEARRAY Doesn’t Do

• It doesn’t provide a residual. CLEARRAY only treats water that’s passing through the chamber. Water sitting in the tub between soaks—with people in it or not—needs a sanitizer present in the water. That’s your chlorine, bromine, or FROG @ease.
• It doesn’t balance the water. pH and alkalinity are still on you (though they’re easier to hold when you’re dosing less).
• It doesn’t replace draining. Dissolved solids still accumulate; Sundance recommends a drain and refill about every three to four months.

Your Sanitizer Options With CLEARRAY

Because CLEARRAY works alongside a residual sanitizer rather than replacing it, you get to choose what that sanitizer is:

In our showrooms, the most popular combination by far is CLEARRAY + FROG @ease: CLEARRAY oxidizes in the circulation loop, SmartChlor holds the residual automatically, and the owner’s job shrinks to a cartridge swap every few weeks and a monthly shock. We stock the Sundance-specific @ease system, linked below.

The Ownership Routine

With CLEARRAY doing the heavy lifting, Sundance’s recommended routine is short:

• After each use: Add a small dose of sanitizer (or let your @ease cartridge handle it).
• Weekly: Test and balance pH and alkalinity.
• Monthly: Rinse the filter.
• Every 3–4 months: Drain and refill.
• Yearly: Replace the CLEARRAY UV-C bulb and your filters.
• Always: Let SmartTub® (on compatible models) send you the reminders so you don’t have to track any of it.

Standard on Every Sundance

CLEARRAY isn’t an upgrade or a package—it’s standard equipment on every Sundance acrylic spa, from the 680 Series through the 980, and it has been factory-installed since 2012. Sundance is part of the Jacuzzi® family, and CLEARRAY Active Oxygen is shared across both brands. The series differ in filtration (MicroClean Ultra on the 980 and 880, MicroClean on the 780, MicroClean Mini on the 680) and in whether True Water is available as an upgrade, but the ozone-plus-UV-C treatment is the same in all of them. If you’re comparing a Sundance against another brand, that’s worth remembering: the water-treatment technology most competitors sell as an option is in the base price here.

Troubleshooting Quick Hits

• Water losing clarity or sanitizer demand rising: Check the bulb’s age first (replace yearly), then clean the filter, then confirm your residual and balance.
• A faint ozone smell at the cover: A small amount of off-gassing is normal; Sundance’s low-output design keeps it minimal. A strong smell means it’s time for a service check.
• Cloudy water after a party: Run CLEARRAY On-Demand if your model has it, shock, and clean the filter—heavy bather load simply outpaces any system for a few hours.
• Chlorine won’t hold: Make sure you’re maintaining a residual (CLEARRAY alone won’t), check for a worn bulb, and test for high cyanuric acid if you’ve been shocking with dichlor.
• Not sure the system is running: The UV chamber and ozonator sit in the equipment bay; if you suspect a fault, call us rather than opening it up—UV-C light is harmful to eyes and skin.

Frequently Asked Questions

Does CLEARRAY mean I don’t need chlorine?

No. CLEARRAY is an oxidizer that destroys contaminants as water passes through its chamber, which dramatically reduces how much sanitizer you need—but it doesn’t leave a residual in the water between soaks. You still maintain a small, steady level of chlorine, bromine, or a FROG @ease cartridge. CLEARRAY makes that amount small; it doesn’t make it zero.

What’s the difference between CLEARRAY and a regular ozonator?

A regular ozonator injects ozone and stops there. CLEARRAY injects a low dose of ozone and then passes the water by a UV-C lamp, which does two things: UV-C destroys the DNA of bacteria and viruses directly, and it energizes the ozonated water into ‘active oxygen’ through an advanced oxidation process that’s more powerful than ozone alone. The ozone also clears dissolved solids so the UV-C can reach more of the water. It’s a sequence, not just a sum.

How often do I replace the CLEARRAY bulb?

Once a year, per Sundance—and that’s the only routine maintenance the system needs. A UV-C bulb’s germicidal output degrades before its visible light does, so replace it on schedule even if it still appears lit. We stock genuine Sundance CLEARRAY replacement bulbs and can set up Autoship so you never miss it.

Can I use FROG @ease with CLEARRAY?

Yes—it’s the combination we recommend most. Every Sundance spa is FROG @ease ready, and FROG makes a Sundance-specific @ease system. CLEARRAY handles oxidation in the circulation loop while the SmartChlor cartridge maintains a steady, self-regulating residual, so you never hand-dose. Together they’re the lowest-touch routine a Sundance can run.

Is CLEARRAY standard on all Sundance spas?

Yes. CLEARRAY Active Oxygen is standard on every Sundance acrylic spa across the 680, 780, 880, and 980 Series, and it has been factory-installed since 2012. The series differ in filtration (MicroClean Ultra on the top two) and in whether the True Water upgrade is offered, but the ozone-plus-UV-C treatment is in all of them.

How does True Water relate to CLEARRAY?

True Water is an optional upgrade on the 980 and 880 Series that layers a nanobubble system on top of CLEARRAY. Nanobubbles continuously lift oils, bacteria, and contaminants so the filter can remove them; Sundance says the result uses up to 80% less chlorine than salt systems and up to 95% less than traditional hot tubs. CLEARRAY stays in the system—True Water adds to it.

At Leisure Time Inc., we sell and service Sundance spas running CLEARRAY every week, and most of the water issues we see come down to two things: a bulb that’s past its year, or an owner who heard ‘UV and ozone’ and stopped maintaining a residual. Get those two right and CLEARRAY is as hands-free as advertised. Bring us your model and a water sample, and we’ll help you choose between chlorine, bromine, and FROG @ease, dial in your balance, and put your bulb and cartridges on Autoship so the system just runs.

Ozone to clear the way, UV-C to finish the job, active oxygen in between—that’s CLEARRAY, explained. And we’re here to help you run it right.

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Tags: CLEARRAY, Tech Explained, Active Oxygen, UV-C, Ozone, Sundance Spas, Hot Tub Water Care, MicroClean, True Water, Idaho