As a kid, I maintained the our pool’s chemicals, but I never mastered the hot tub chemicals! YOU are a scientist. This wasn’t covered in my “Physics for Social Science Majors” class.
So far, I sprinkle a little chlorine every once in a while and that’s it. I bought test strips but haven’t used them recently. Maybe some anti foam if there are bubbles. The tub has a built-in ozonator.
And I sprinkle Japanese pond scum in it when I can’t smell it anymore. Found this stuff when I bought my first hot tub in VA in the 1990s, and I love it. I was able to buy it in CA, until the store stopped carrying it. I can’t believe I was able to find it again, online, when I bought this tub. It is a very nice minerally scent, not really flowery. It makes me feel peaceful - I think because it conjures up memories of soaking in the tub with my kids 30 years ago. (This can would last at least 2-3 years, and tints the water slightly blue-green.)
Oh hello - it’s available on Amazon now! https://www.amazon.com/Magma-Onsen-Bath-Salt-17-6/dp/B005A0Z8UC
“ Description
Magma Onsen Beppu (Umi Jigoku) is a bath salt containing spray-dried powder of hot water from the famous Beppu Umi Jigoku hot spring in Oita Prefecture, which is famous for its "Jigoku tours" and fragrances. The elegant fragrance and marine blue water warms the body from the core and removes the fatigue of the day. Enjoy a relaxing and soothing hot spring experience at home!”