Uh oh... well, you need to put the tanks on a concrete foundation, or do reinforcement to the floor below to support that kind of weight. Is there a way you can do the fish room in the basement? If you don't put them on the concrete, or don't reinforce, the tanks could potentially break the floor and fall into the basement. I have NO IDEA of what you'd need to do for bracing for that kind of project, as they will be spaced out everywhere throughout an entire room, I'd suggest contacting a structural engineer to advise you with that one. You'll certainly need additional support, though. For example, at my house, which is 70 years old, has solid hardwood framing throughout, and was build before the days of plywood, has diagonally laid 2" thick wood planks as the sub flooring, hardwood flooring on top of that, and even with placement along an exterior wall- we are going to need to brace the floor when I upgrade to my 180 gallon tank in a few mos. and you're going to have WAY more gallons/weight load than that. We're talking thousands of pounds concentrated in one room. Again, not trying to rain on your parade- I just don't want to see you facing the problems I am mentioning.