Aperture and Sharing photo streams

[drmelb1]

I have just uploaded about 19,000 photos from Aperture albums to photo stream sharing. Some I wanted to share, others I wanted to share with me and have as an extra backup to my external HD.
"Your start up disc is nearly full." I now realise that in creating the photo stream albums all my photos have been duplicated - or at least I think that is what has happened. I have deleted a few photo stream albums and there I see them in the trash - many many GBs.
Any way around this? I assumed that the photos would be referenced after the photos in the original albums not duplicated.
Is there any way of seeing them in the library?

 

[Bear]

Photostream is not a backup.. It only holds up to a thousand photos and they can expire after being on the stream for 30 days.

Photos that come in to Aperture via photostream are considered masters by Aperture. It has no way of knowing that they are duplicates of other masters you have.

 

[drmelb1]

Thank you for your reply.
I realise that photo stream only holds them there for a short period of time but the shared photo stream albums are held indefinitely if I am not mistaken?

I havent downloaded from Photo Stream.