how to keep Acronis from sending old backups to recycle folder-uses up too much space!

Using Acronis True Image 2017 for Windows, and my backup location is a NAS device. I have tried my best to set up my image backups and file backups settings in Acronis so that it makes one copy, then increments a while, then eventually makes another fresh copy and deletes the old one. However, the old ones don't really get deleted; they get moved to a subfolder in my backup location called "recycled". so they are still there taking up space, and eventually my NAS disc fills up. The way I usually know this is about every 6 weeks I'll get an email notification that my backup failed. I'll look and sure enough, the disc will be full. So how do I make it not put old files in "recycled" but just delete them instead? Thanks, Andy