Beltmann, I say no mandarin due to the BB. You can have your >10 posts or Loverotties irrelevant 20k+ posts, it doesnt matter. In my 190g, I was going to go BB, I actually WAS BB for a little, with a good 150 lbs of rock Id estimate. Even then I didnt feel that it would have been safe for a mandarin. I added sand pretty much for the looks, and so I could keep a mandarin and jawfish.
IF you MUST have a mandarin, there are probably ways to do it. First Id wait til you do have a good pod count... then Id get more. Have a fuge with tons of rubble rock, macro algae and sand. Then have some more rubble rock in rain gutter net zip tied together, making little bundles you can rotate. I would have a good 5 of these guys, and rotate them every 1-2 days, from sump to display, 1 at a time. I think if you are religious with that method, you could probably keep a mandarin successfully. I know that if it were me, it would end up not being worth the hassle.