You don't NEED an ozonator; there are pros and cons. There are others here who know more about them, but my impression is that it's not really worth it.
Bromine is often recommended (instead of chlorine) as a sanitizer for hot tubs. Don't know if you're familiar with chlorine chemistry, but if you are, be advised that bromine works quite differently! There's a "primer" for using bromine posted in this "Spa/Hot tub care" section; refer to that.
The "mineral" sanitizers usually contain metals, copper, maybe silver, maybe zinc. These DO kill the nasty microbes, BUT the problem with them is they don't kill them fast enough. And metals in your water can cause staining.
The nice thing about a hot tub is that you can try different sanitizers sequentially, since you have to drain and refill every few months. Bromine is more stable in high temperature water, and combined bromines are not "used up" like combined chlorines (cc's). Bromine also sanitizes in a wider pH range than does chlorine. But bromine can't be stabilized against sunlight (not a problem if you keep the tub covered when it's not in use). Bromine is also more expensive than chlorine.
One product that's really not necessary in a pool (except maybe an indoor pool
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but almost ESSENTIAL in a spa is an enzyme treatment. With the smaller volume of water, a spa will have a higher level of organic contaminants. To prevent the "tub ring," use an enzyme treatment such as Spa Perfect or Scum Buster. The enzymes help "digest" organics so that your sanitizer doesn't have to work as hard.
Other folks can chime in about ozonators; I don't know a great deal about them, but you can keep your hot tub sanitized just fine without one.