Q: Photo Library - iCloud duplicates how to remove

All, anyone know anything about OSX/IOS  "Photos" app ability to detect and remove duplicate photo9?  My "Photos" library has 63,299 photos & 2135 videos as of May 2016 and at least 10,000 + of these photos are duplicates (based on a scan by Photosweeper). I have checked the result of the Photosweeper scan by doing a manual visual comparison and check of original image files in iphoto library (using show location function) and confirmed these 10,000+ photos are identical duplicate images with different file names located in  different parts of photo library database. 

So what is going on  and how do I stop 10-15% of my image library being duplicate files!!! I will raise this directly with apple support as paying for the 1TB icloud service to cover my very large "Photos" library which should probably just be a Large Photo Library!!!!

Some other comments for those who have a duplicate  problem:

- The old iPhoto application used to "detect duplicates" when importing but the new "Photos" app does not do this. Anyone know about this?

- I saw some documentation from apple saying that the icloud scans for duplicates in "Photos" when in the icloud but clearly not working or it does not work if the duplicates also exist in the imac version of the "Photos" library. 

- Watch out for apps that claim to find duplicate "photos" and are recommended on various websites, a number of these only work with the old iphotos app not the new "Photos" app (as I found out after paying and downloading them). If you need a photos duplicate remover that work with "Photos" check review and stay away from any app that does not clearly and expressly state that it works with "photos" and has been reviewed since the release of the Photos app.

+ I paid US$10 for "Gemini" the duplicate finder and was a complete waste of time as did not work with "Photos" app (this was not clear from documentation or support and when I raises this with Macpaw support they told me gemini does not support photos and told me to buy another macpaw app - I told them to go jump in a lake). 

+ I found Photosweeper very good as you can set for exact match or variables (eg accidental burst photos that are 0.1s apart but 99.99% identical) and  you can then right click to view original file / image in library to manually check for duplicate (if you are paranoid like me) - there are lots of other paid apps that also do this so shop around