cross-posted from: https://wolfballs.com/post/11267

So you'd need a living space that has two bathtubs / showers, or a separate bathtub and shower, so you can shower or bathe in the other one, and use the other as a hot tub.

That out of the way, can you reuse water and treat it like pool water is treated, and/or run a filter, and heat the water some way or cool it (for ice baths), to convert a regular bath tub in to a hot tub?

I couldn't find too many links online.

I think those outdoor backyard stock tank pools are interesting too.

Any thoughts on DIYs related to the topic?