海門温泉
Kaimon OnsenOperated by · 豊後高田市観光まちづくり株式会社
塩
Chloride
- Color
- colorless and clear
- Taste
- strongly salty, moderately bitter
- Odor
- very faint metallic
Sodium-Magnesium Chloride spring
pH 6.2NeutralStrong saltHigh silica
Composition fingerprint24.4 g/kg dissolved · Hypertonic
Na⁺62
Mg²⁺22
Ca²⁺13
Cl⁻86
◀ CationsAnions ▶
- Sodium Na⁺
- salt's cation — pairs with chloride to make the water salty.
- Chloride Cl⁻
- table-salt anion — coats the skin and holds heat in.
Known good for
- Warmingcold sensitivity
- Smooth skindry, rough skin
- Cutsminor wounds
A sodium-magnesium chloride spring labeled 'kyo-ensen' (strong-salt) on the certificate — at 24.45 g/kg total dissolved it approaches ocean salinity. Clear at the wellhead but with a forceful salty-bitter taste and a faint iron note; the lab sample yellows and turns slightly cloudy within hours. Neutral pH, hypertonic, with a generous 168.5 mg/kg of metasilicic acid — bathers leave with a thick mineral coating clinging to the skin.
Sampled at wellhead·Analyzed Apr 17, 2023·大分県衛生環境研究センター·Cert no. 衛理研第242号の1