So a couple weeks ago we got the 90 gallon set up. I wanna say March 21st or 22nd. It is on the second floor sitting room, above the living room. The whole thing probably weighs about 1200 pounds in total, tank, stand, water, and gravel. We got the fish in(its a native tank) recently. I noticed a couple days ago a tank shaped cracking in the ceiling, right where the tank is above the living room. Too much of a coincidence. I think it has something to do with the tank. I really don't want to cause any structural damage to the house or have this tank come crashing through. The house was built in 1874 if it helps. Here are some pics: