This is a very old topic. I used to run a pool in the 1990s and used the then popular Teledyne Laars ozone generators. They were very expensive junk; burnt out every year or so. Since then, on another installation, I have used various others, most recently a Prozone one, which is also expensive junk.
They use two main principles.
The powerful ones (Teledyne) just do a corona discharge into an air stream passing through them. These fail by carbonisation of the various insulators, which shorts out the inverter output and - being a crap design - blows up the inverter.
The less powerful ones use a UV source to make ozone in the air inside the box, and you pass air through the box. These fail by the UV tube burning out, which usually blows up the inverter
These pics shows the failed tube in a Prozone unit - also an expensive piece of junk despite being made in the US
The problem is no matter what one buys, it is ALL junk. It is as if there was a parallel universe where everybody making stuff is useless and the customers just pay whatever... $1k/year for replacing this junk.
I am wondering whether one should simply buy a UV lamp, of the type which makes ozone, like this
(most of these are just UV; you have to get a specific type that makes ozone, but they look the same)
and when that blows up you just unscrew it and screw in a new one.
Is there some better way to make ozone, which is more reliable?