Wonder if instead of moving the sand I have now into the 45 and adding more sand, I could just move the sand over then add about 30 lbs of CC on top of it. That would give me about a 3/4" sand bed topped off with a few inches of CC. Then with all the rock sitting on top of it. I think that sound like it might be ok. I would hate to have to give up the sand it came from a good source, and would help seed all the new stuff.

Now should I place this thing in the back corner, and run it diaginal to the opposite front corner, or have it run front to back in the center?