Well I have a 240 right now in my townhouse. I wouldn't consider it the second floor where it's located, It's kinda in between. In the room where it's at theres no other rooms below it and the ground is like 8-10 feet below it or maybe less, it's hard to tell. So far so good, I estimate my tank to be around 2300lbs. This house is less than 5 years old, so it is realitively new. I was wondering if I could go bigger, but it looks like I am pushing it right now. Guess I'll have to wait till I move to get something bigger.