All things hot tub:
https://www.poolspaforum.com/forum/i...tubs-amp-spas/
All things water chemistry:
https://www.poolspaforum.com/forum/i...ter-chemistry/
I use a submersible pump and either drain it into my bar sink just inside the door with garden hose, or if using the faster larger diameter hose I go into the floor drain in the basement.
My neighbour drains his pool into the swale (very illegal) I wouldn't risk the fine myself.
I might be tempted to use the ravine. I wouldn't think the chemicals would be that bad as to kill the vegetation.
Seems to me the repair guys once drained mine into the back yard. No issues.