I don't question your 30+ years just the UV.
If I tell you that you could have the same results without out the UV you'll scratch your head

But then again what ever works for you don't change it.
For me I never enter my house through the front door........... and I never had a disease and I always change water in my blue buckets and never in a different color if that makes sense

Oh and part of the reason I'm not go through the front door is that if I ever run into a uninvited guest I can blow them through the front door as I never like my front door anyway but the lady of the house does and believe me you don't want to fight her.
To UV or not to UV that always is a question that will never be solved we can agree on that