There have been some recent discussions regarding pH.
http://www.canreef.com/vbulletin/showthread.php?t=71271
http://www.canreef.com/vbulletin/showthread.php?t=71728
and similiar mentions about pH in this thread:
http://www.canreef.com/vbulletin/showthread.php?t=71079
I think there is a general consensus in all of those threads that if you don't see anything wrong in your tank, you don't really need to mess with pH. If you do it could lead to problems that you aren't currently having.
