What Is the Difference Between an Air Bath and Whirlpool Hydro Jets?

Air massage and whirlpool hydro massage move two different things through their jets. An air bath uses a blower under the tub to push air through small jets in the seat, the base of the seat and the footwell floor, so the water around you fills with a gentle, effervescent full-body bubble massage, while hydro jets, also called water jets or whirlpool jets, use a pump to recirculate your own bath water and send it back out as a forceful stream you can aim at the back, hips, legs and feet. The air system is explained from button to bubbles in What is an air tub and how does air bath therapy work?, and this page sets the two systems side by side, lists what each one brings with it, and answers why some Ella models are not offered with air at all.

How Each System Works

Hydro massage is the whirlpool style. When you press the Water button, the hydro pump draws bath water in through the inlet cover and pushes it out through the jets. The in-line heater and the ozone generator both run automatically with the pump, so the water is held at the temperature you filled it and sterilized as it circulates. The intensity dial on the deck is an air control on a small hose rather than an electrical part, and turning it adds or removes air in the water stream to make the massage firmer or softer. Many hydro jets can be aimed, and the foot jet nozzles can be opened, reduced or closed by turning the center of the jet face. The parts and the care they need are covered in What Are Hydro Massage Jets on a Walk-In Tub?, and someone searching for a hydrotherapy tub is looking for exactly this, a walk-in tub ordered with a hydro package, as What is a hydrotherapy tub with built-in spa jets? explains.

Air massage is a separate system with its own push control. The button is pneumatic: pressing it sends an air signal through a thin tube to the control box under the tub, and the control box starts the blower. The blower pushes air through lines under the tub and out through three groups of brass jets, upper jets in the seat and backrest, bidet jets at the base of the seat, and lower jets in the footwell floor. The speeds are chosen by counting presses. The first press is high speed, the second press is medium, the third press is low, and a fourth press turns the system off. On the digital touchpad you touch the air bubble icon once to start, use the plus and minus buttons to change intensity, and hold the icon for two seconds to turn the air off. About 20 minutes after the air pump is turned off, Auto Purge starts on its own and runs for 120 seconds to blow residual water out of the air lines. It cannot be stopped and is normal even if it begins while you are still in the bathroom. The video on this page shows where Ella places the air jets, including hip, feet and bidet jets, and introduces the three-speed system with Auto Purge.

Air, Hydro and the Combinations Compared

What these differences mean for you comes down to feel and warmth. Hydro is the forceful option because water is being pushed at you, and it is also the only system that keeps the bath at temperature, since the in-line heater comes only with hydro packages and runs only while the hydro pump is running. Air is softer because the jets are only blowing air, and the air lines look after themselves with Auto Purge, but an air-only tub does not warm the water, so you fill it hot from the faucet. A dual tub gives you both and adds the chromatherapy light, which comes with every dual and triple package but not with hydro alone.

Water Level, Cleaning and the Automatic Cycles

The two systems also ask different things of you. Before starting a hydro pump, fill the tub 1 to 2 inches above the highest hydro jet, because a pump run dry is permanently damaged and that damage is not covered by the warranty. Once a month, run the vinegar flush: combine 2 cups of white vinegar with 2 cups of water, fill the tub to one inch above the highest jets, add the mixture, run the tub for 10 minutes, then drain. Clean the pump inlet cover at the same time and skip bath bombs, which clog the jets. Air lines clear themselves with Auto Purge, so you do not flush after every bath, and an individual air jet cannot be permanently closed off because removing one lets air escape from the system. A light humming with nothing on is the ozone generator running by itself and is normal on a hydro tub, and a tub that starts by itself about 20 minutes after an air bath is the purge, not a fault. The everyday name for the air system, and Ella's second kind of bubble, the Infusion microbubble therapy, are covered in What Is a Bubble Tub and How Does Air Massage Work?.

Why Some Models Do Not Offer Air

Whether a model offers air comes down to the therapy packages that model is built for. A therapy package is the set of pumps and systems installed under the tub at order time, and jets follow the package rather than the model name, as What Is a Therapy Package on a Walk-In Tub? explains. The tub shell stays the same whichever package you choose, and what changes is the equipment underneath, so a model offered without air is simply a model built for a hydro or soaking configuration only.

• The Standard ships in a single hydro configuration with 18 hydro jets on an 8.1A 900W pump. It has no air system, and therefore no purge cycle after a bath.
• The Standard, Zen and Flow are the hydro-only tubs in the line.
• The LayDown tubs take one therapy at a time and have no LED light.
• The Front Entry has no Hydro plus Foot option and does not offer the LED light with any package.
• The Deluxe ships as a fixed Air plus Hydro package, and the ShaK and Big4One ship with the digital-controller Air plus dual Hydro package included, with microbubble optional.

Because the package is built into the tub at the factory, it cannot be changed after the tub is built. If having air matters to you, settle the package with your Ella dealer or the team at (800) 480-6850 before production, and tell them which model you have narrowed down so they can confirm the therapy packages it can be ordered with.

Choosing Between Air and Hydro

If you want pressure that reaches a sore back or hip, hydro is the system that delivers it, and the intensity dial exists to soften it when it feels too strong. If you want to be surrounded by warm bubbles without a strong stream, air is the gentler choice, and pressing to the third setting gives the softest bubbles. Many Ella tubs combine both so the choice is made bath by bath rather than at order time, and those dual massage tubs also come with the chromatherapy light. Keep the schematic that shipped with your tub, because it names the package and its circuits, and the team will ask which package is on your order before answering any jets question.

Watch: Walk-In Tubs Featuring Three Speed Air Massage & Auto-Purge Technology | Ella’s Bubbles with chapters and a full transcript.

Related Guides

• My walk-in tub turned on by itself: the air massage Auto-Purge is normal
• Hydro massage vs air massage: what each system does and how to use the controls
• What Are Air Massage Jets on a Walk-In Tub?

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