I have a 75 gallon brick style withe really thick glass. I have a 29g sump underneath. A gallon of water weighs 8 pounds. I weigh a tad over 200. Thats 200 lbs, with all of that weight resting on two things, my feet. If I was scared of me and three friends standing in an area the size of a tank, I would not move there. It's all about how that weight is distributed. Oh yeah, we live on the second floor. I will be putting a larger aquarium in our apartment, unless we get a house before that. Our apartment manager stated that people had much larger aquariums than mine, so it set my mind at ease. Our apartments were built last year, and they are "nice", so I trust they are built a little better than an average apartment.