Sauna Dekor Spa Solutions engineering team, Istanbul · project and press enquiries: Alican Aykaç, Managing Partner
Last updated: 23 October 2026
Short answer: a swim spa is a hot tub stretched into a swimming lane: one factory-built shell, about 4.5 to 6 m long and 2.35 m wide, where a pump-driven current lets you swim on the spot. Sauna Dekor Spa Solutions supplies and installs Wellis swim spas, and this guide sets out the 6 things that decide whether one fits: size, filled weight, power, water, place and delivery.
The models, dimensions and ratings below are Wellis’s own published figures, linked at the end. Where we have worked a number out from them, such as the load on the slab, we say so. Our part of a project is everything around the shell: the base, the route in, the electrical supply, the drain and the commissioning.
What is a swim spa?
A swim spa is a single acrylic shell that holds 2 things: a swimming lane with a counter-current, and usually a seating area with massage jets. Wellis’s W-Flow models adjust that current from 0.4 to 2.5 km/h in 6 steps, from a gentle float to a steady training pace, in a footprint of a little over 10 to 14 m².
The current is what makes it a swim spa rather than a large hot tub. Pumps push water along the lane towards the swimmer, who swims against it and stays in one place. Turn the current down and the same water becomes a place to walk, stretch or float; the seats at one end work like a hot tub.
Wellis’s W-Flow models differ in length and in how much of the shell is given to seats rather than to the lane. A household that mainly wants to swim takes a longer lane; a family that wants a hot tub with a swimming option takes more seats.
How is a swim spa different from a pool and a hot tub?
A swim spa sits between the 2. A pool gives a real length of water but is built on site, with excavation, a concrete shell and a plant room. A hot tub gives warm water and massage but no swimming. A swim spa gives a short lane and massage seats in 1 finished unit, delivered rather than built.
That difference in how each one is made decides the project. A lap pool is designed around the plot and needs a long, straight site; our page on swimming pools in Dubai covers the shell, the plant and the permits it brings. A hot tub, described in our guide to what a jacuzzi is, is small enough to go almost anywhere, and a plunge pool is a small pool built in place for a dip rather than a swim.
A swim spa asks for neither excavation nor a long site, but it brings questions of its own: the weight on the slab, a route wide enough for the shell, a dedicated electrical supply and a drain for several thousand litres. Those are the questions the rest of this guide answers.
How big is a swim spa?
On Wellis’s figures, swim spas in its W-Flow range run from 453 cm long for the Danube W-Flow to 550 cm for the Amazonas W-Flow and 600 cm for the Rio Grande W-Flow. All 3 are 235 cm wide and 147 cm high, which means the width and height are fixed and the length is the choice.
| Wellis model | Size (L × W × H) | Water volume | Jets | Counter-current |
|---|---|---|---|---|
| Danube W-Flow | 453 × 235 × 147 cm | 5,913 litres | 24 | W-Flow |
| Amazonas W-Flow | 550 × 235 × 147 cm | 8,000 litres | 26 | W-Flow, 0.4–2.5 km/h in 6 steps |
| Rio Grande W-Flow | 600 × 235 × 147 cm | 6,600 litres | 41 | W-Flow |
The longest shell does not always hold the most water. The Rio Grande W-Flow is the longest of the 3 but gives more of its length to a lounger and seats, so it holds less water than the Amazonas W-Flow. The lane, not the shell, is what a swimmer feels, so we compare the layout drawings as well as the outside sizes.
The footprint matters as much as the length. Add a clear walkway on the sides where the cover lifts and where the service panels open, and the area a swim spa really takes on a terrace is larger than the shell alone.
How heavy is a swim spa when it is full?
Several tonnes. On our arithmetic from Wellis’s figures, an Amazonas W-Flow weighs 1,250 kg empty and holds 8,000 litres, so about 9,250 kg rests on 12.9 m², around 715 kg/m². A Danube W-Flow comes to about 6,960 kg on 10.6 m², around 655 kg/m², before anyone gets in.
We take one litre of water as one kilogram; swimmers and the cover add to these totals. Wellis does not publish a dry weight for the Rio Grande W-Flow on the page we read, so we do not give a load for it.
On a garden slab at ground level this load is rarely a problem if the base is flat, level and continuous under the whole shell. On a roof terrace, a podium or an upper floor it is the first question, and it is answered by the building’s structural engineer, not by us. What we do is give the engineer the numbers: the footprint, the filled weight, where the shell bears, and where the drain and service access are.
What power and water connections does a swim spa need?
A dedicated electrical supply sized to the model, a water point to fill it and a drain to empty it. Wellis rates the Amazonas W-Flow at 1 × 35 A, 230 V minimum and 1 × 60 A, 230 V optimal; the Rio Grande W-Flow at 1 × 25 A, 230 V or 3 × 16 A, 400 V; and the Danube W-Flow at 1 × 35 A, 230 V or 3 × 20 A, 400 V.
The supply is a job for the project’s licensed electrician, who sizes the cable for the run, fits the residual-current protection and isolator the local code requires, and connects to the unit’s control box. Our side is coordination: the model’s rating, the cable entry point on the shell and the isolator position go to the electrician before the slab is cast.
The heating load is modest by comparison: Wellis lists a 3 kW heater for the Amazonas W-Flow and 2 × 3 kW heaters for the Rio Grande W-Flow. Water care runs on the unit’s own filtration and disinfection, set on the control panel at handover.
Draining matters more than filling. Emptying a shell of 5,900 to 8,000 litres for cleaning sends that water somewhere, so the drain route is agreed at the survey: a foul drain, a gully sized for the flow, or a pump-out. Warm, heavily used water also needs steady disinfection, which is why the World Health Organization treats hot tubs and similar pools as a group of their own.
Where can a swim spa go in a Gulf villa: garden, basement or roof?
All 3 are possible, and each brings 1 deciding question. In the garden it is the route in for a 2.35 m wide shell. In a basement it is the air: a warm water surface indoors needs extract and dehumidification. On a roof it is the structure, because the filled weight runs to several tonnes.
In the garden, the shell needs a flat, level, continuous base, shade over the water and a cover between uses. A swim spa that sits partly below the deck needs a pit with drainage and service access on the side where the equipment panels are; the panels must still open once the deck is built.
Indoors, the questions are those of any warm pool hall: humid air, condensation on cold surfaces and an air handling system that keeps the room dry. Our page on the indoor pool in Dubai sets out that climate control. On a roof, nothing is ordered until the structural engineer has confirmed the slab and a lift plan exists.
How is a swim spa delivered and lifted into place?
As one piece. A Wellis W-Flow shell is 2.35 m wide and 1.47 m high, and 4.53 to 6.0 m long depending on the model, so every gate, corridor, corner and ramp on the route has to clear it. Where the route cannot, the shell is lifted in by crane over the villa or onto the roof.
We survey the route before the unit is ordered: gate widths, turning space, overhead cables and canopies, ground that a lorry and a crane can stand on, and the lifting point on site. For a crane lift, the crane company’s lift plan and any road permit come into the programme, along with the rules of a tower’s building management or a gated community.
Rooftop units are where this matters most. A crane lift onto a roof is booked and permitted before the unit ships, and the base, the electrical supply and the drain are ready before it arrives, so the shell is placed, levelled and connected in one visit.
Who supplies and installs it?
Two parties, for 2 different things. Wellis manufactures the swim spa in Hungary, at factories in Dabas and Ózd, and warrants it on its own terms: for the Rio Grande W-Flow and the Danube W-Flow its pages state 10 years on the shell structure and 3 years on engineering components. Sauna Dekor Spa Solutions supplies the Wellis unit and installs it.
Our installation covers 8 steps: site survey, base and load check with the structural engineer, delivery and lift plan, supply of the chosen model, electrical coordination, plumbing and drain, placing and levelling, and commissioning with the control settings explained at handover. Around the shell, the same project can include decking, shade, an outdoor shower or a nearby outdoor swimming pool; where a client wants only a hot tub, our jacuzzi page for Dubai covers that route.
Keeping the 2 roles apart avoids the most common confusion after handover. A fault in a pump, a heater or the control panel is a manufacturer’s warranty matter, which we report and coordinate with Wellis. A fault in how the unit was placed, levelled or connected by us is ours.
Who builds this
Sauna Dekor has designed, manufactured and installed saunas, steam rooms, hammams, pools and cold plunges since 1987: 40 years of manufacturing in Istanbul, in our own facility in İkitelli OSB, with a team of 19 employees and 5,000+ projects in 35+ countries. We work under TS EN ISO 9001:2015, certificate no. 202025106. Our offices are in Istanbul (İkitelli OSB), Dubai (Latifa Tower), Bodrum, Germany (Monheim am Rhein) and Boston (66 Long Wharf, Unit 4B). We also have representative offices in Haarlem and Doha.
The swim spa on this page is a Wellis product; we supply it within a project and carry out the installation, and its specifications, ratings and certificates belong to Wellis as its manufacturer. On our installation work we give a 24-month warranty on workmanship; the swim spa itself carries the manufacturer’s own warranty, confirmed for the exact model in the order documents.
Frequently asked questions about swim spas
What is a swim spa used for?
Swimming on the spot against an adjustable current, and sitting in warm water on massage seats. On Wellis W-Flow models the current runs from 0.4 to 2.5 km/h in 6 steps, so the same shell serves a gentle float, a walk in the water or steady swimming.
How long is a swim spa?
Wellis W-Flow swim spas run from 453 cm for the Danube W-Flow to 600 cm for the Rio Grande W-Flow, all 235 cm wide and 147 cm high on Wellis’s figures. Part of that length is seats and the counter-current unit, not swimming lane.
How much water does a swim spa hold?
Between about 5,900 and 8,000 litres for the 3 Wellis W-Flow models in this guide: 5,913 litres in the Danube W-Flow, 6,600 in the Rio Grande W-Flow and 8,000 in the Amazonas W-Flow. That volume decides the drain the site needs for emptying.
Can a swim spa go on a roof terrace?
Only if the structure can take it. A filled Amazonas W-Flow puts about 715 kg/m² on its footprint before swimmers, on our arithmetic from Wellis’s figures. The building’s structural engineer confirms the slab first, and the shell then needs a crane lift plan.
What electrical supply does a swim spa need?
A dedicated circuit sized to the model and installed by a licensed electrician. Wellis rates the Rio Grande W-Flow at 1 × 25 A, 230 V or 3 × 16 A, 400 V, and the Amazonas W-Flow at 1 × 35 A, 230 V minimum, with 1 × 60 A optimal.
Who makes the swim spa and who installs it?
Wellis manufactures it in Hungary and warrants the unit on its own terms. Sauna Dekor Spa Solutions supplies the Wellis swim spa within a project and installs it: survey, slab check, delivery, electrical and drain coordination, placing, commissioning and a 24-month warranty on our workmanship.
Sources
- Amazonas W-Flow swim spa — Wellis. 550 × 235 × 147 cm, 8,000 litres, 1,250 kg dry, 26 jets, W-Flow 0.4–2.5 km/h in 6 steps, 1 × 35 A minimum and 1 × 60 A optimal at 230 V, 3 kW heater.
- Rio Grande W-Flow swim spa — Wellis. 600 × 235 × 147 cm, 6,600 litres, 41 jets, 1 × 25 A 230 V or 3 × 16 A 400 V, 2 × 3 kW heaters, 10-year shell and 3-year component warranty.
- Danube W-Flow swim spa — Wellis. 453 × 235 × 147 cm, 5,913 litres, 1,047 kg, 24 jets, 1 × 35 A 230 V or 3 × 20 A 400 V, 10-year shell and 3-year component warranty.
- The Wellis story — Wellis. Company history and factories in Dabas and Ózd, Hungary.
- Guidelines for safe recreational water environments, Volume 2: Swimming pools and similar environments — World Health Organization, 2006. Hot tubs and similar pools as a category of their own for water treatment.
