Wow, thanks. I'm going to try to answer most of the questions I've received in one message as I'm overwhelmed by the quick multitude of responses.
As I stated earlier, I haven't collected any room temperature data, yet. So, I don't know the unfrozen mosaicity. It is very possible that the crystals are simply mosaic at RT, too. I have tried flash-cooling in liquid nitrogen and "gas cooling" in the cryo-stream, I didn't notice a difference in the diffraction pattern. My solvent content is on the high side about 67%. Additional crystal details, I set the trays up at 20 degrees. The crystals take about 2 weeks to appear and another week to grow to full size. The crystals are bipyrimidal and often 150x150x300 although sometimes smaller. Typically, there's about 34-39% MPD in the well solutions. The well solution freezes clear and I don't get any ice rings in my diffraction patterns. I've tried looping the crystals directly out of the drop or adding a few microletters of well solution and then looping, I didn't notice a difference. I've been hesitant to start adding extras fearing crystal cracking. I did however switch to freezing directly in the automounter puck which was my one low mosacity crystal but I had plenty of other crystals in the puck that weren't better then before. I was wondering if the MPD concentration could cause problems and sounds like it might be. So, with the crystals I have I'll try higher MPD to dehydrate and try freezing in lower MPD concentration or add some other cryoprotectants to my current well solution. Although, I might have to go find some propane. If that doesn't work maybe, I'll try seeding at lower MPD concentrations or pressure freezing. Thanks again, Mary
