Tell her its less than 500lbs. Stuff was built just fine back then if not better than now. It would also help to put the tank on a support beam if you can. But against a wall would be fine.
Tell her a couch, her, and her husband probably weigh just as much as the tank and they dont fall through the floor when they sit down.
40Gal Planted- 10Gal RCS Planted
6 Julii corys, 1m Furcata Rainbows, 2f 1m Bose Rainbow, 2 mystery snail