A simple thermal spring drawn from beneath Sakae in central Nagoya. Hypotonic and neutral, it is lightly mineralized at 169 mg/kg of dissolved solids, so the water reads soft rather than assertive. Bicarbonate makes up roughly four-fifths of the anions and a measurable dose of metasilicic acid rides along with it, which is what gives the water its smooth touch on the skin. At the wellhead it is colorless and clear; by the time the sample reached the laboratory it had taken on a faint yellow tint.
Good for
Recovery
Warmth and buoyancy lower stress markers and improve sleep; habitual bathing is linked to lower rates of depression.
fatigue, stress
Full composition
The bar is each ion's share of charge (mval%) within its group; over 20% names the spring. Gases, silica and trace metals are measured by mass only.
- Sodiumsalt's cation — pairs with chloride to make the water saltyNa⁺23.8mgP5 national68%
- Calciumsettling and calming; can leave a white mineral bloomCa²⁺6.7mgP21 national22%
- Potassiumminor; matters for drinking limitsK⁺2.5mgP24 national4%
- Magnesiummild; a laxative if you drink itMg²⁺0.70mgP23 national4%
- Iron (II)rusts brown in air; iron for anemia when drinkableFe²⁺0.70mgP59 national2%
- AmmoniumNH₄⁺0.10mgP23 national0.7%
- ManganeseMn²⁺0.10mgP36 national0.0%
- Bicarbonate"soda" — softens skin, leaves it smoothHCO₃⁻77.3mgP39 national82%
- Chloridetable-salt anion — coats the skin and holds heat inCl⁻8.6mgP11 national15%
- Fluoridetrace; drinking limits applyF⁻0.50mgP30 national2%
- Hydrogen phosphateHPO₄²⁻0.30mgP58 national0.7%
- Metasilicic acidmetasilicic acid — a natural moisturizer for silky skinH₂SiO₃47.4mgP26 national
- Metaboric acidmetaboric acid — mildly antibacterialHBO₂0.30mgP7 national
- Free carbon dioxidefizz — widens blood vessels (strong above 1000 mg/kg)CO₂6.0mgP30 national
- ArsenicAs0.0020mgP9 national
- CadmiumCd< —mg
- CopperCu< —mg
- Mercurytoxic trace — part of the drinking-safety checkHg< —mg
- LeadPb< —mg