I was getting ready to clear the Black Bowl Dragon challenge and took a quick look at PDX to make sure there weren't any funky boss skills that I had forgotten about. Nope, looked pretty straight forward, so I went in with the team I've been using for these Bowl Dragon challenges: Revo Leilan, R/L Leilan, XMas Ronia, Revo Minerva and Revo Leilan friend. Entered the dungeon and saw zero red orbs then something clicked in my brain... looked back at PDX. No Fire/Water orbs. Whoops. I almost quit, figuring the stamina loss wasn't the end of the world, but it occurred to me that the early floors could easily be cleared with sub elements at 20.25x, and the entire team was max skilled, so making fire orbs should be a non-issue. Sure enough, cleared it pretty easily. But yeah... don't forget to check those orb restrictions!