Ozone: How It Works and How to Use It SafelyUpdated an hour ago
Some Vital+ chillers have a built-in ozone system that helps keep your plunge water clean between changes. Used as designed, it’s safe and needs almost no effort from you. Ozone is a powerful oxidiser, though, and it can irritate your lungs if it builds up in the air. Here’s how it works and the simple rules that keep it safe.
Does my chiller have ozone?
| Chiller | Ozone |
|---|---|
| Ultra X1 | No |
| Ultra X2 (Original) | No |
| Ultra X2 (Pro) | Yes |
| Ultra X4 / Acrylic Chiller | Yes |
| Ultra Max (Original) | No |
| Ultra Max (Pro) | Yes |
| Ultra Ice | Yes, as standard |
Not sure which version you have? Check your user manual, or look for the ozone indicator on your chiller’s display.
How it works
- It’s made inside the chiller. A small generator turns oxygen from the air into ozone (O₃) and mixes it into the water as it circulates.
- It breaks down contaminants. Ozone oxidises sweat, body oils and other organic matter, and helps control bacteria in the circulating water.
- It doesn’t linger. Ozone is unstable. Within minutes, it breaks back down into ordinary oxygen, so it leaves no chemical residue in your water.
- It runs in cycles. The system switches on and off rather than running constantly. On the Ultra Max and Ultra Ice, you can adjust the ozone settings from the control panel or the Tuya Smart app.
What ozone doesn’t do
Ozone works alongside your filters. It doesn’t replace them. Because it disappears so quickly, nothing is left in the water to protect it between cycles. You still need to clean or replace your filters on schedule, change your water regularly and keep the tub clean. See Cold Plunge Water Maintenance and Filter Maintenance Full Guide.
Why ozone needs respect
The ozone that matters for your health is the ozone that escapes from the water into the air you breathe. Breathing in ozone can cause coughing, a sore or scratchy throat, chest tightness and shortness of breath, and it can make asthma worse. That’s why workplace safety limits for ozone in air are set very low.
In a well-ventilated space, the small amount your chiller produces disperses quickly and isn’t a concern. Problems happen when ozone is allowed to build up, for example:
- Running the chiller in a small, closed room, cupboard or enclosed space
- Lifting the lid straight after an ozone cycle and breathing in close to the water surface
- Adding extra ozone devices, or a damaged or modified ozone system
The rules for safe use
- Never be in the water while the chiller is running. Switch your chiller off before you get in, every time. This also stops the ozone cycle.
- Let the tub air out before you get in. If an ozone cycle has just run, take the lid off and give the surface 5–10 minutes to air out before your session.
- Keep it ventilated. Your chiller and tub need a well-ventilated space, with at least 100 cm (39 in) of clear space around the chiller’s vents. Indoors, open a window or door, or run an exhaust fan.
- Schedule ozone for when nobody is using the plunge. If your chiller lets you set ozone times, run cycles overnight or while you’re away.
- Don’t put your face close to the water to check the smell.
- Don’t add or modify anything. Never add a separate ozone generator, and never open the chiller casing. The ozone generator runs on high voltage.
- Keep children and pets away while the chiller is running.
- Have asthma or a lung condition? Speak to your doctor before using a plunge with an ozone system, and take extra care with ventilation.
What’s a normal smell?
| What you notice | What it means | What to do |
|---|---|---|
| A faint, fresh smell near the tub, like the air after a storm | Normal ozone activity | Nothing. Keep the space ventilated. |
| A strong, sharp or bleach-like smell, or one that makes you cough or gives you a headache | Too much ozone in the air | Switch the chiller off, ventilate the space, move away and contact us. |
| A musty or “swampy” smell | The water, not the ozone | See Unusual Smell from Your Chiller. |
If anyone has trouble breathing, move them into fresh air straight away. If symptoms don’t settle quickly, seek medical help.
Ozone and your equipment
Over time, ozone is hard on rubber. Check the O-rings and seals whenever you change your filters, and replace any that are cracked, flattened or hard. Avoid bleach and chlorine shock products. They aren’t needed alongside ozone and can damage your chiller. See Cleaning & Descaling Your Cold Plunge for products that are safe to use.
When to contact us
- The ozone smell is strong or keeps coming back, even in a ventilated space
- The ozone indicator shows a fault, or never comes on
- Your chiller keeps shutting down, and you’ve already checked the water level and filters
Send us your order number, your chiller’s serial number and a photo of the display. Please don’t try to repair or remove the ozone system yourself.