This page explains the therapy schematic titled Air + Hydro + Hydro Foot + Microbubble Therapy with Digital Controller, the component diagram Ella's Bubbles publishes for the Shak and Big4One walk-in tubs. It is the only single-seat diagram in the schematic family that calls for three dedicated wall outlets, so it answers most of the electrical questions that come up when one of these large tubs is planned, installed or serviced. Everything below comes from that schematic PDF (revision date printed 01-08-26) and from the printed Shak and Big4One specification sheets.

The Only Single-Seat Diagram with Three Outlets

Most single-bather Ella therapy schematics show two wall outlets. This one shows three, labeled #1, #2 and #3, and every one of them carries the same printed requirement: wall outlet, GFCI protected, dedicated line, 20 AMP, 120 Volts. The reason is the size of the equipment stack on the Shak and Big4One. Each tub runs two hydro pumps (one for the seat jets and one for the foot and calf jets), an air pump, an in-line water heater, an ozone generator and an LED light, with a microbubble water pump and pressure vessel available as an option. Spreading those loads across three dedicated circuits is how the diagram keeps each line within its 20 amp rating.

If you are planning the electrical rough-in for one of these tubs, share the PDF with your licensed electrician before the tub arrives. The electrical requirements by model page gives the broader picture across the whole lineup.

Which Tubs It Lists

The diagram prints two model names: Shak and Big4One. Both are extra-large outward-swing door tubs with the same therapy architecture, which is why they share a single schematic. You can read more about each model on the Shak profile and the Big4One profile.

The Eight Numbered Components

The legend on the schematic numbers eight components. The descriptions below follow the printed wording.

1. Air Massage System. Refer to the technical drawing for jet count; variable speed pump with auto purge; ON/OFF Digital Controller.
2. Seat Hydro Massage System. Hydro pump; hydro massage air flow intensity control; ON/OFF digital controller.
3. Foot Hydro Massage System. Hydro pump; hydro massage air flow intensity control; ON/OFF button.
4. Infusion Microbubbles (Micro Bubble Therapy System). Microbubble pump; pressure vessel; ON/OFF button. This system is optional and has its own push control.
5. In-Line Water Heater. Control box.
6. Electronic Component Controller. Control box, drawn as the Master Box on the diagram.
7. Ozone Generator. Ozone sanitation system.
8. LED Light. Chromatherapy.

Two things are worth noticing. First, the in-line water heater sits in the foot hydro loop, so warm water is maintained through the foot and calf circuit while that pump runs. Second, the heated seat and backrest option listed on the spec sheets is not drawn on this diagram.

Digital Controller for Air and Seat Hydro; Buttons for Foot and Micro

The Shak and Big4One mix two control styles, and the schematic makes the split clear. The air massage system and the seat hydro massage system are switched from the digital controller. The foot hydro massage system and the optional microbubble system each use a physical ON/OFF button on the deck. Both hydro systems also have their own air flow intensity dial, so you can tune the seat jets and the foot jets separately. The spec sheets confirm the same arrangement: seat hydro and air are "Controlled by Digital Controller," and foot and calf hydro uses "On/Off Push Control." The LED chromatherapy light is also run from the digital control pad.

This matters when "the buttons do nothing," because the seat jets and the air bubbles are started from the digital controller. The push controls versus digital touchpad page walks through the two control styles in more detail.

Electrical Printed on the Diagram

The schematic prints these electrical values exactly.

The diagram also shows relay switches on the microbubble and heater or foot circuits, with Load 1 and Load 2 leaving the control box. For the individual pump ratings you need the spec sheets, which print them like this.

Both spec sheets describe the equipment as 115V 60Hz and require dedicated GFCI protected electrical lines, with every fixture connected to a GFCI outlet or a GFCI breaker. Pump amperage values can change based on availability, so if your electrician needs the exact rating for the pumps in your unit, confirm with the team at (800) 480-6850 and have your order details handy.

Breaker Questions on These Tubs

Because this is the three-outlet diagram, the first thing to check on a Shak or Big4One that trips a breaker is whether all three dedicated 20 amp GFCI lines actually exist. A common shortcut is to plug two of the three cords into the same circuit, which works until the seat pump, foot pump and heater all run at once. If the tub trips only when a particular therapy is added, confirm the cord serving that therapy has its own line. The breaker or GFCI keeps tripping page covers the full checklist.

Download the official document: Air + Hydro + Hydro Foot + Microbubble Therapy with Digital Controller schematic (Shak, Big4One)

Common Questions