Sole Uno

Sole Uno is a brine bathing and sauna complex in Rheinfelden, in the Swiss canton of Aargau, and forms part of the Parkresort Rheinfelden. It is built around Rheinfelder Natursole, a natural brine the operator describes as one of the strongest in Europe. The site lists four pools across indoor and outdoor areas, a sauna landscape with indoor cabins and three sauna huts in the garden, a salt inhalation hall, a massage lounge and an adjoining fitness gallery.

Thermal water

According to the operator, the brine is extracted at the Saline Rheinfelden-Riburg salt works from a depth of around 200 metres and piped to Sole Uno. The site describes Rheinfelder Natursole as a protected brand name rather than an ordinary saline solution or an artificial salt bath, and states that it is mixed with calcium-rich and magnesium-rich local drinking water and warmed to between 33 and 36 degrees Celsius. Brine is a salt concentration rather than a temperature, and the site gives the two separately for each pool.

Pools

The outdoor brine pool in the park covers 250 square metres at 32 to 34 degrees Celsius with about 3 per cent salt, and the site lists bubble loungers, massage jets, a waterfall and a current channel. The intensive brine pool holds 200 square metres only 0.60 metres deep at 36 degrees Celsius with 12 per cent salt, which the site says lets bathers float stretched out. The indoor brine pool covers 290 square metres at 33 to 34 degrees Celsius with about 3 per cent salt and is roughly 25 metres long for swimming lengths, with a raised bubble pool at 36 to 38 degrees Celsius built into it.

Sauna and wellness

Indoors the site lists a Finnish sauna at about 90 degrees Celsius with hourly aroma infusions, a bio sauna at 55 degrees Celsius and a steam bath at 45 degrees Celsius. Outdoors the operator describes three sauna huts: an earth sauna half sunk into the ground at 110 degrees Celsius, a hexagonal fire sauna of Finnish polar pine seating about 24 people at 100 degrees Celsius, and a Russian banya brought from Siberia seating about 50 at 70 to 80 degrees Celsius. The site states that the saunas are used textile-free, that the area is mixed at all times, and that its facilities may be used only from the age of 14. A separate salt area adds a brine inhalation hall at 35 to 37 degrees Celsius, where brine is atomised over a wall of blackthorn branches.

Opening hours

The site states that the bathing and sauna landscape is open daily from 08:00 to 22:30, with last entry at 20:30 and bathing ending at 22:00. Entry can be reserved at least 24 hours in advance, and the operator publishes a live occupancy indicator.