Digital BW, The Print

Hello all,

My first bottles of my CFS filled with FS-N are about 2/3 empty.  I
thought I remember reading on this list that one should not go much
below 1/3 of ink left before adding more.  New 4 oz. bottles of ink
just arrived from inkjetgoodies today.  Since I've never done this I
want to make sure I do it right.  Do I just unscrew the caps on the
bottles and simply pour more ink in?  Any need to shake or mix the
bottles, either the old ones or new ones first?  Perhaps it is as
simple as it sounds but if someone could re-assure me or add any hint
or two of something I might be forgetting I'd appreciate it.

Thanks.

Best regards,
 Richard