Hydrogen Peroxide is very effective in killing bacteria in water. Back in the early 80's, I was using it with an automated chemical feeder in conjunction with an Aquazone Compressor Ozonator. Other than the peroxide, it was chemical free. Spa water always looked great and odor free.
Here comes the problem; the peroxide was tearing up equipment on an annual basis and if you ever got it on your skin in straight form, it would burn, it was 37% peroxide.
I don't believe it is a true sanitizer, it probably wasn't when I was using it either.
hottubber...