What is the difference between air massage and hydro massage jets?

Hydro massage moves water: a pump draws your bath water in through the pump inlet cover and pushes it back out through jets in the tub wall as a directed, high pressure stream that you soften or strengthen with an intensity dial. Air massage moves air: a separate blower pipes air through sealed lines to small jets in the seat and floor, so what you feel is a blanket of rising bubbles with three speeds rather than a stream aimed at one spot. Which systems a model can carry is decided by its therapy packages, the sets of pumps installed under the tub at order time that What Is a Therapy Package on a Walk-In Tub? describes, and that is also why a few models are built without an air option.

How Jets de massage hydro Work

A hydro massage system is a water loop. When you start it, the hydro pump draws bath water in through the pump inlet cover, sends it through the in-line water heater and pushes it back into the tub through the hydro jets, so the water you are sitting in is the water doing the massage. The Hydro package adds that pump together with the in-line heater and ozone sterilization, which switch on and off with the hydro pump, plus a push button to start the system and an intensity dial on the deck.

The dial is what makes hydro massage adjustable. Turning it up introduces more air into the jet stream for a stronger flow, and turning it down reduces the air for a gentler flow. The second video on this page shows the dial in use and explains that every Ella tub with hydro massage has one, whether the system is started from push buttons or a digital touchpad. The schematics explain why it is always there: the dial is an air control on an air hose rather than an electrical part, so it stays mechanical on every controller family, as What the Air + Hydro Digital Controller and Heated Seat Schematics Show lays out.

The jet count follows the package and the model rather than the therapy itself. The Standard ships as a hydro massage configuration with 18 hydro jets, the Capri has 15 hydro jets arranged with 9 in the upper section and 6 in the lower section, and a Transfer spec sheet lists 22 hydro jets for its Hydro package, including the strategically placed foot massage jets that come with the hydro side of a package. Microbubble therapy is a third system that is often confused with hydro, and What Is the Difference Between Thérapie par microbulles and Jets de massage hydro? separates those two.

How Air Massage Jets Work

Air massage uses its own air pump, a variable speed blower, which pushes air through fully plumbed, sealed lines to air jets set into the seat and between the legs. Only air moves through those lines, and the bubbles rise up through the bath water around you. Because the system is blowing air rather than pumping water, the pressure is gentler than hydro. Because the lines are sealed, an individual air jet cannot be permanently closed off; removing one lets air escape from the system.

The push control gives you three speeds from one button. The first press starts the air massage on high, the second press drops it to medium, the third press to low, and a fourth press turns the system off. There is no reverse ramp, so pressing through to the third setting is how you reach the softest bubbles. On a 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, the Auto Purge starts on its own and runs for 120 seconds to blow residual water out of the air lines. It is fully automatic, cannot be stopped, and is normal even if it begins while you are still in the tub. What Is a Bubble Tub and How Does Air Massage Work? covers the air system in more depth, including what happens with bubble bath and how the pneumatic button works.

Air and Hydro Side by Side

Read across the rows and the practical difference is clear. Hydro is the system you aim and adjust: the stream is directed, the dial sets its strength, and the in-line heater and ozone switch on with the pump. Air is the system you relax into: three speeds from one button, gentler pressure, and an Auto Purge that clears the lines afterward. The two Transfer rows show how the systems share one shell. The same tub lists 22 hydro jets when hydro is the only system and 11 hydro jets plus 17 air jets when air is added, and both figures are correct for their packages, because the jet openings are divided between the two systems rather than stacked on top of each other. Any package with two systems also brings the LED chromatherapy light, which hydro alone does not include.

Why Not Every Model Offers Air

The jets follow the package rather than the model name, and each model is built for a defined set of packages. A model's spec sheet prints jet counts and electrical lines per package, so when the sheet lists no air package, that model is not built for an air blower. Most single-seat models offer the full menu, which is why the question usually comes up on the handful of models that are fixed or limited:

• The ShaK and the Big4One ship with the digital-controller Air plus dual Hydro package included, with microbubble optional, so air is always on board.
• The Deluxe ships as a fixed Air plus Hydro package.
• The Standard ships as a hydro massage configuration with 18 hydro jets, a push control and the intensity dial.
• The LayDown tubs take one therapy at a time, so a LayDown is air or hydro, never both, and has no LED light.
• The Front Entry has no Hydro plus Foot option and does not offer the LED light with any package.
• A soaking package has no air or hydro controls at all, because there are no pumps under it.

The package cannot be changed after the tub is built, so if air massage matters to you, settle it with your Ella dealer or the team at (800) 480-6850 before production and ask which packages the model you are weighing is offered with. Walk-in Tub Model Highlights notes that where therapy features are offered they can include heated seat and back, hydro jets, air jets, microbubbles and hydrofoot therapy, and that most models can also be built as a soaker with no jets.

Does Either Therapy Need an Extra Device Connected?

Neither therapy needs anything connected beyond what is installed under the tub at the factory. For hydro, the water does the work: the pump recirculates the bath you have already drawn, and the only things added along the way are heat from the in-line heater and ozone from the sterilization unit. For air, the blower supplies the air and the sealed lines carry it to the jets. There is no external unit to attach, no separate water supply for the jets, and no accessory to buy afterward. The only connections your home provides are the dedicated electrical lines your electrician runs, and the number of lines follows the package, printed on the spec sheet beside the jet count.

The push buttons themselves are pneumatic rather than electrical. Pressing one sends a puff of air down a small hose to the control box, which switches the pump on. The first video on this page shows that hose between the push control and the control box and how it is secured by pushing and twisting it onto the nipple, since a loose air tube is the usual reason one massage goes quiet while the other keeps working. Care follows the package too: hydro tubs get a monthly vinegar flush and a pump inlet cover check, while an air system clears itself with Auto Purge.

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