How do air and hydro massage differ, and why do some tubs skip air?

Hydro massage and air massage are two separate systems that can sit under the same tub shell. Hydro massage uses a water pump that draws your bath water in through the pump inlet cover and pushes it back out through the jets for a deep, targeted massage, while air massage uses a three-speed blower that pushes air through its own set of jets for a gentler massage. Some Ella models skip air because they are built as hydro-only platforms with no blower at all: the Standard, Standard60, Zen, Zen60 and Flow. What Is a Therapy Package on a Walk-In Tub? explains how these systems are bundled at order time; this page sets the two side by side and lists which models offer which.

Hydro Massage: Water, Heat and an Intensity Dial

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: the heater holds the water at the temperature you filled it, and the ozone sterilizes the water as it circulates. The intensity dial on the deck is not an electrical part. It is an air control on a small hose, and turning it up introduces more air into the jet stream for a stronger flow, while turning it down reduces the air for a more gentle flow. The video on this page shows the dial in use on a hydro tub. Many hydro jets can be aimed, and the foot jet nozzles can be opened, reduced or closed by turning the center.

Jet counts belong to the package rather than the model name. The Standard ships with 18 hydro jets on an 8.1A 900W pump, the Elite's hydro package has 16 jets with 10 in the seat and 6 in the foot area, and the Transfer family's Hydro Massage package lists 22 jets, 16 seat and 6 foot. Tubs with independent foot massage add a second pump and dial for the foot and calf jets. Before you start the pump, fill the tub 1 to 2 inches above the highest hydro jet; running a pump dry causes permanent damage that is not covered by warranty. What Are Hydro Massage Jets on a Walk-In Tub? covers the jet assembly itself.

Air Massage: A Blower, Three Speeds and Auto Purge

Air massage adds a three-speed blower rather than a water pump, so nothing recirculates your bath water. With push controls the air button starts on high: press once for high speed, a second time for medium, a third time for low and a fourth time to shut the system off. On the digital touchpad, touch the air bubble icon once to start, use plus and minus to set the intensity, and hold the icon for two seconds to turn it off. Push Button Controls vs the Digital Touchpad: Operating Every Deck Control walks through both panels.

Because a little water flows back into the air piping and the floor and seat jets after an air bath, every air system has Auto Purge. About 20 minutes after you turn the air massage off, the blower starts on its own and runs for 120 seconds to blow that water out through the jets. The cycle cannot be interrupted, it stops on its own, and it is normal even if it starts while you are still in the tub. What Is Auto Purge on a Walk-In Tub? has the full explanation, including why some printed manuals describe the trigger incorrectly.

Air and Hydro Side by Side

What the differences mean: hydro is the firmer, warmer system and the one that needs a care routine, while air is the gentler system that cleans its own lines. The intensity dial exists so a hydro massage that feels too strong can be softened without changing systems. If you want both feels in one tub, the dual Air plus Hydro package puts a water pump and a blower under the same shell, each with its own jets and controls.

Why Some Models Have No Air Massage

The reason is the platform rather than the package menu. The Standard, Standard60, Zen, Zen60 and Flow are built as hydro-only platforms, so they carry no air blower and therefore no Auto Purge cycle, and they are also the sit-down tubs that cannot be ordered as soakers. Because the LED chromatherapy light comes with every dual and triple package but not with hydro alone, a tub ordered with hydro only does not include the light either. Common Model Questions lists these exceptions alongside the other model limits.

Other models shape the menu in different ways. The Ultimate is offered with massage only. The ShaK and Big4One ship with the digital-controller Air plus dual Hydro package included, with microbubble optional, and the Deluxe ships as a fixed Air plus Hydro package. The Front Entry has no Hydro plus Foot option and no LED light with any package. The LayDown tubs take one therapy at a time and have no LED. The two-seat Tub4Two, Companion, Escape and Big4Two always include at least one massage system. Any Ella tub ordered with the three-speed air massage has Auto Purge, whether the air came alone, as Hydro plus Air, or in a triple package, which covers air packages on the stainless-door, Ultra, outward-swing, two-seat, Transfer and LayDown families.

Choosing Before the Tub Is Built

The package cannot be changed after the tub is built, so settle it with your Ella dealer or the team at (800) 480-6850 before production. Spec sheets print jets and electrical lines per package, which is why a Transfer sheet can list 22 hydro jets for the Hydro package and 11 hydro plus 17 air jets for Hydro plus Air, and both are correct. Care then follows the package: hydro tubs get the monthly flush of 2 cups white vinegar with 2 cups water in a tub filled 1 inch above the highest jets, run for 10 minutes and drained, plus a pump inlet cover check; air systems self-clear with Auto Purge; a soaker needs neither. Keep the schematic that shipped with your tub, because it names the package and its circuits, and have your model, serial number and package name ready for any jets question at ellasbubbles.com/support.

Related Guides

• What Are Air Massage Jets on a Walk-In Tub?
• Hydro massage vs air massage: what each system does and how to use the controls
• Why Does the Air Massage Blow Cold Air? There Is No Heating Element

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