Maintaining Alk levels

^ Good advice, thanks.

I found the following info from Randy. It should be useful to anyone with this problem. He also addresses the ULNS question.
http://www.reefcentral.com/forums/sh....php?t=1993192

With my tank, I am dropping alkalinity by 1dKH each day. 3 days later, it is now at 7.6dKH so I just need to do maintenance doses and stick to smaller water changes of 10%. I think my STN occurred because my ALK probably dropped to 5dKH and then I did a large water change which raised it back to 10dKH.