Sorry, not going to touch this.

I've seen pool/hot tub valve, piping and control set-ups that looked good . . . in a magazine. In real life, they've all been a mess. I could probably figure it out on site, but not via the Internet, especially when getting it wrong means major freeze damage!

Regarding chems: for your own safety, you need to check hot-tub levels before and after each use. People won't do that, which means hot-tubs are often unsafe, which is why I've never been willing to 'support' hot-tubs here.