[new but handy]

my 180 plus my 55g sump are on the second floor of my house. no problem with yours. If you are still worried, exterior walls and the walls around your stairs are gauranteed bearing walls. Most walls in your house are not bearing. 2x10 floors are stronger than TJI's. If your tank is 36x18 you are pretty much gauranteed to hit at least 2 joists. Most joists are on 16" centers. Aquattro is right about everything, plywood spreads the weight more than you would believe. I weigh 240#(don't tell anyone) I would noy hesitate to pick up my 120# girlfriend, my 40# kid and my 90# dog. I would stand on 1 foot for about 1500#'s per square foot. no problem