It is an ozone unit fitted in the powerbox. It adds automatic ozone sanitation to the pump and filter system: an ozone cycle runs by itself for 30 minutes every day, with no chemicals needed. The water stays cleaner for longer and you can go up to 12 months between water changes, depending on usage, bather hygiene and routine maintenance.
The Sub-Zero Plunge
The Sub-Zero Plunge
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- Cools to -2°CReal ice, not just cold water
- Up to 12 months of clean waterAutoClean Water Care System, no chemicals needed
- 2-year warranty5-year upgrade available
- Speak to the ownerGet a call back within 30 minutes

The Sub-Zero Plunge
The upgrade
AutoClean Water Care System
Cleaner water for longer. No chemicals needed.
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01
No chemicals needed
An ozone cycle runs by itself for 30 minutes every day. There is nothing to buy, measure or pour in.
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02
Cleaner water for longer
Ozone treats the water while the filter traps dirt, hair and lint. Two systems working together.
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03
Longer between water changes
Up to 12 months between water changes*, against up to 6 with Standard Filtration. Less draining, refilling and waiting for the water to get cold again.
*Depending on usage, bather hygiene and routine maintenance. With either option, the filter needs a rinse every 2-3 weeks.
Joel, Owner and Product Designer
Got questions? Speak to me directly.
No call centre and no sales script. I designed the Sub-Zero Plunge and I know it better than anyone. Ask me about setup, space, power, running costs or which colour to choose, and you'll get a straight answer.
Three Tub Colours
Black Galaxy, Ivory Stone and Blue Speckle. Each tub is a solid drop-in built from reinforced FRP with steel beams inside and a marine-grade gelcoat finish.
Choose Black Galaxy for a deep, dramatic look, Ivory Stone for a clean, bright one, or Blue Speckle for a fresh blue. Same plunge, same performance.
Two Lids. Your Choice.
Every Sub-Zero Plunge comes with a hard lid on hinges. It is solid, lifts up and out of the way, and has a lock.
The soft top lid is a $200 upgrade. It is lightweight, folds in half and holds itself in place with hidden magnets.
Commercial-Grade Cooling Power
This isn't your standard cold plunge. It's a commercial-grade powerhouse that cools all the way down to -2°C, creating true ice-bath conditions. Once the temperature drops below freezing, large chunks of ice form naturally, for an authentic ice bath experience few systems can match.
The Powerbox: Organised and Automated
Everything that runs your plunge is organised in one place: the temperature controller, the pump connections and the power. Set your exact temperature on the unit or from your phone, anywhere from -2°C to 15°C, then step back. It runs itself.
Easy Maintenance, Minimal Effort
Keeping your plunge in top shape couldn't be simpler. Just rinse the filter every 2-3 weeks. It takes less than five minutes.
Spacious, Comfortable, and Built for All
Our cold plunge measures 153 cm long, 72 cm wide, and 82 cm high. Tested personally by our founder (6 ft tall, 95 kg), it offers generous space and comfort, and even users up to 6 ft 6 in fit with ease. Stretch your legs fully, keep your shoulders relaxed, and sink in up to your neck. Beginners can start on the built-in step and ease in gradually.
Frequently Asked Questions
What's the difference between the three colours?
Only the colour of the tub. The plunge and its performance are identical.
Which lid should I choose?
The hard lid on hinges is included, and it has a lock. The soft top lid is a $200 upgrade: it is lightweight, folds in half and is held in place by magnets.
How much is shipping and when will it be sent?
Shipping is calculated at checkout based on your postcode. In-stock orders are dispatched within 48 hours, and we'll send you a tracking number.
How cold does the plunge get?
The Subzero Plunge is a beast, it can reach temperatures as low as -2°C. At this point, you'll see large chunks of ice forming.
While this is impressive, we recommend plunging at around 0°C. This way, you can enjoy all the benefits without having a big chunk of ice poking you during your plunge
How do I set the temperature?
You can set a desired temperature directly on the included digital thermometer or using the app. It can be any temperature you like. Set it and let the big rig do the rest.
How much maintenance is involved?
Very little. We recommend rinsing the filter every 2-3 weeks to keep it in good condition.
Water changes are needed about every 6 months with Standard Filtration, where you add chlorine or peroxide yourself, and up to every 12 months with the AutoClean Water Care System. Both depend on how clean you are before plunging and how often you use it.
How do I empty it?
Using the included pump, it takes about 10 minutes. All you need is a garden hose and the pump does the rest.
How big is it? Will I fit in?
The plunge is 153cm long, 72cm wide, and 82cm high. We tested various sizes and found this one fits people up to 6ft 6in comfortably.
We also added extra width for broader shoulders, so you won't have to hunch like in some other plunges.
Plus, the length is designed to ensure you can fully submerge your head.