welcome to PTF 
roud:
high rise (over 8 stories) buildings generally have reinforced concrete slab flooring, so long as the tank is near a wall, especially walls between rooms, or along the outside wall of the building which are closest to support beams, it should be fine. if the space between the floor and your downstairs neighbor is actually wood joists and plywood, then anything over 120gal should be avoided. keep in mind if your tank leaks, and water ruins your downstairs neighbor's ceiling and furnishings, you will be liable, not the building or the tank fabricator, so if you have home owners insurance, you should update it to reflect this potential liability since 100gal of water can do thousands of dollars in damage. Review the house rules of your building to make sure there are no clauses specifically about Aquariums so if not, then don't ask for permission. try to get a stand or plateing that distributes the weight better, so you don't damage any of the wood panel flooring with just few pressure points. also, plan the tank move carefully to allow for the doorways, elevators, and hallways to be able to accommodate a huge tank, and the 3-4 guys needed to maneuver it properly. if you buy the tank new from a store, pay for white glove service to be sure they not only deliver it, but unpack the stand and tank, then position and level it properly. if the tank will block an electrical outlet, make sure they cut out a hole in the back of the stand so you can reach your hand through and get at it properly while working from within the stand.
roud:high rise (over 8 stories) buildings generally have reinforced concrete slab flooring, so long as the tank is near a wall, especially walls between rooms, or along the outside wall of the building which are closest to support beams, it should be fine. if the space between the floor and your downstairs neighbor is actually wood joists and plywood, then anything over 120gal should be avoided. keep in mind if your tank leaks, and water ruins your downstairs neighbor's ceiling and furnishings, you will be liable, not the building or the tank fabricator, so if you have home owners insurance, you should update it to reflect this potential liability since 100gal of water can do thousands of dollars in damage. Review the house rules of your building to make sure there are no clauses specifically about Aquariums so if not, then don't ask for permission. try to get a stand or plateing that distributes the weight better, so you don't damage any of the wood panel flooring with just few pressure points. also, plan the tank move carefully to allow for the doorways, elevators, and hallways to be able to accommodate a huge tank, and the 3-4 guys needed to maneuver it properly. if you buy the tank new from a store, pay for white glove service to be sure they not only deliver it, but unpack the stand and tank, then position and level it properly. if the tank will block an electrical outlet, make sure they cut out a hole in the back of the stand so you can reach your hand through and get at it properly while working from within the stand.
