Great news about the chamber. You are probably seeing water desorbing over night and that leak is most likely a virtual one.
I cut through my alumina materials and all glass and quartz like butter with my diamond band saw. Most folks have no need for, or can't afford such items, but it will indeed take pure diamond to cut that alumina tube well.
The dremel diamond cutoff wheel is available and should be in their advanced accessories. I purchase most of mine at hamfests from the tool vendors where they are about half price ($~10).
Richard Hull
Created on Thursday, May 17, 2001 3:12 PM EDT by Richard Hull