I just stumbled upon this, sounds like a great idea and very unique- the question is will anything live in there with the temperature swings, not to mention other possible hazards.....how about a spilt beer in the tank. 
http://blogs.trb.com/sports/custom/business/blog/2010/06/marlins_stadium_update_no_600.html
http://blogs.trb.com/sports/custom/business/blog/2010/06/marlins_stadium_update_no_600.html