Rob,
Just wondering , What kinds of x-tra nutrients are you referring to? I am battling cyano in my 3 yr old reef. I added new PH's because I figured maybe the old ones were not performing at their best, changed my bulbs to new ones and I am tying to feed my fish less often. I also, added more a fresh clean up crew.
So, Long story short, Old Tank, new problem, dont get it?
Thanking you kindly, Kim