Listers,
   
  When you get a "bright red laser beam" you have gone past the point where 
agglomeration has set in.
   
  You may be adding more silver but the ionic content is starting to decrease 
as the ions start to group into larger particles. That's why the laser gives 
you a red beam.
   
  Stop when the beam first begins.
   
  If you would plot the current vs time as y;ou brew and stop when the current 
line breaks to the right. That is the point of maximum silver ions.
   
  I have hundreds of data plots and spectrophotometer reading to prove it.
   
  "Ole Bob"