Wow...can't imagine how much you have spent on the rock alone..such good quality rock!
Hmmm...I worry about that anemone though...I have a feeling the foot of the anemone might actually upset the deep sand bed. Maybe can replace it with a substitute like a plate coral (heliofungia)? These look identical if not nicer compared to anemones...and definitely easier to keep.
Heh...you NO3 problem same as mine...got a shock when I bought a salifert. LoL! Can try floating a basket with some caulerpa in your main tank to help with nitrate export.