Thank you Mike and BMbikerider! You have confirmed my experience. My impression was always that Blix lasts quite a while in an airtight container. However, some recent posts in apug that blix starts to go off soon after mixing have made me very concerned. My main worry about blix is that I would not be able to tell immediately when it's not working since retained silver would show up much later after the print is washed, dried and hung on the wall for a few weeks. Thanks guys, you made me feel better.