I'm also interested in non-chlorine systems. Keep in mind, however, that SWG (saltwater generator) is a chlorine system. Many people use and like it.

We use the Del AOP system which utilizes UV and ozone together. It's used in conjunction with a chlorine dispensing system as a supplement. In our case, we choose SWG's.

Running the filtration system 24/7 using the AOP, is the most beneficial. Variable speed pumps are a consideration for energy savings and will be a requirement come July 2021 as per The Department of Energy.

In most cases you can keep your chlorine levels at .5 PPM and still have the ability to properly sanitize.

You still must maintain and balance other chems namely, cyanuric acid, total alkalinity, pH and calcium hardness. It's not the end all be all system. There's no setting and forgetting.

For SWG systems, use a sequestering agent on a regular basis. There are types specifically for SWG's.

I'm not comfortable with any of the ionization systems as they use copper and silver as a means to purify. Both are heavy metals which I would not to be swimming in. Others may argue that point. I looked into these systems more than 30 years ago.

Keep pool water chemistry simplified, and you'll have great pool.

The other issue with an ozone only system is that the bateria on the walls and tile of your pool cant ever be sanitized until you shock it. Chlorine via salt cell or reg pool set up is in the water and kills algae/bacteria everywhere the water touches. My pool has both. Ozone gen and reg chlorine feeder tower. Considering you have to shock all pools there isnt a way to avoid chlorine unless you want to pay for the nonclorine shock. Which is still a chemical and very expensive compared to chlorine shock.