Some background...Just moved into a 2nd & 3rd (finished attic) floor condo unit 2 1/2 months ago. My 55 gallon fishtank was actually the first thing in the house due to the terrible hassle of moving it. The house is in the new england area and is very old (1870) but was nicely reconstructed into 4 units of condos 6 years ago. I am a little concerned however that my fish tank may be too heavy and doing damage to the floor. There is deflection in the floors that is mostly only noticeable with a levelling tool, but this is throughout the whole condo and not just the area where the fishtank is located.
The tank is placed about 4 feet from the exterior wall along the side of the staircase leading up to the finished attic. I believe it is perpendicular to the floor joists (I can only tell from the storage compartment in the attic which way the joists run). The door at the top of these stairs is sticking and won't close all the way, and the bathroom door next to it is rubbing slightly. There is a closet door that sticks directly underneath that door as well. There is molding separating about 1/8th inch along the staircase and other slight molding separation throughout the condo. I can't say that this wasn't the case before I moved because the fish tank was first in here and I didn't notice it during the relatively brief inspection. I do know the door sticking has gotten slightly worse. There are some moldings breaking slightly away from the wall along the staircase as well.
I'm just wondering if some of these issues should be expected when you add a 650 lb piece of furniture to an old house, or if I should consider removing or at least moving the fish tank. Some of these changes may have been due to settling after the renovation, and general weather patterns of new england as well. I'm just not sure.