Thrid try did the job

Tried several programs that worked ok, but tended to remove more than I wanted. I had to revive and convert the Aperture library from my backup two times before I tried this app. The problem was how Apple managed the conversion from Aperture/iPhoto to Photos. So I needed this program, special for Photos. It did what it had to do and removed more than 7,000 duplicates. Still have to trash a lot of non-duplicates, but this was a great start.

Stupedia about Duplicate Photos Fixer Pro