Above is the biggest bathtub and my feet. Before being remodeled, this building was like a ruin actually. I do not think that the bathtubs and the wall covered with calcium carbonate was not refurbished.
This facility is in the valley called "Shikaribetsu-kyou" where a variety of hot spring can be savored. Details are at http://www.kanno-onsen.com/
https://www.facebook.com/kannoonsen but written only in English.