I have been going over this question myself only on a much smaller scale, I live on the 2nd floor and I've been worried about getting a 60 gallon(only because the lease says 30 gal.max)! 240 gallons is HUGE!! it's going too weigh a lot!! I couldnt imagine how bad your manager would freak out if they saw a tank that size in your apt. I honestly cant tell you how much weight the floor will hold but I dont think I could even get a 240 up the stairs! Worst case is the tank falls through the floor( even though I admit I have never heard of this happening?) You also run the risk of having to get rid of the tank or getting evicted, and the possibility of the tank fallingover, leaking or cracking and having all that water end up downstairs. I dont want to sound like like a jerk since I'm in a similar situation, but I realize that a set-up that large and most likely ,very expensive does not really belong in most apartments(unless it's one of those fancy pants ones for the rich people!lol) so I have to practice some self-control,and save up the money that something that big will most likely cost me and wait tell I get a house so I can have whatever the heck I want! I hope everything works out for you and that you can get the tank you really want, please follow up with this story as it seems to be a topic of interest lately, since we have lots of MOnster lovers living upstairs/in apartments!