I had an 150 before in a 3rd floor. I've set it next to a wall of course and the structural floor was wood trusses. Never had a problem with the administration, but I can assure they never knew the weight of that thing. It handled right for more than 2 years until we have to move to another apartment in the same complex, this time at floor level.
I wouldn't do it again. Fortunately, I never had a leak and the tank was drilled, lucky for me I never overflowed any thing.
Could imagine what I could happen from having issues like overflowing, or busting a tank over 50 gallons, first soaked carpet then electrical issues, then the management calling at your phone, sounds silly, but that's a real situation.
In another side, I really, really don't think management would like to sign or make in writing a form that it could avoid them from acting legally against you if you end up damaging property, this wouldn't allow them to charge someone with damages, let's said water damage, structural damage or electrical damage. More likely the management would and could ask you for a higher rate deposit so they could absorb repairs from your pocket and any other needs.
But don't believe this, and just think about the pros and cons of what you want to do.