FACSAria stream stability

Fellow flowers:

Being a new FACSAria user, I would appreciate feedback on an issue I have 
encountered.  Here are the two questions:

1-At the BD FACSAria training, every morning the stream, amp, frequency and 
drop breakoff were very reproducible.  However, in our lab, this varies 
tremendously.  Is this normal?
2-Stream adjusted and satellite drops merging as should, used cytometer all 
morning, went to lunch/returned, and Satellite drops had disappeared plus 
when went to adjust....satellite drops emerging from the bottom of the drop 
and unable to move to merge into the top?

We are using the 100 um nozzle because of large and fragile cells.

Please send comments.  Thank you very much.

Sincerely,
Barbara Oppenlander
OHSU
CML Lab
Portland, Oregon 97239
oppenlan@ohsu.edu