Sodium Chloride spring
Component table for Gero Onsen. Dissolved solids run light at 374 mg/kg, placing the water in simple-thermal territory — gentle on the body, low in mineral edge. The clear presence of carbonate ion (CO₃²⁻) signals an alkaline pH, and roughly 60 mg/kg of metasilicic acid contributes the soft, silica-led feel Gero is known for.
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65. Izumi-so, Gero Onsen Went with a tegata for higaeri (listed from 8 to 9 and 18 to 20). Very pleasant and positive staff. They gave a random discount on a small towel and a large towel rental, asking just 100 yen total, and the grandma-owner gave a compliment on my sneakers. The changing room and the baths themselves are very small. Indoor bath is hot+, outdoor is hot-. Water is clear, with a film effect on the skin afterwards. There are frog figurines. Honestly, compared to other onsens in Gero — skippable, but it's hard not to note the very warm attitude of the staff.
