I called the office and asked if it was ok to keep a 75gal tank in my upstairs apt and they said it was ok and that all the apts were waterbed safe. But im still a little worried b/c ive read that waterbeds spread their weight out and are equivalent to a fridge. I know i should put it perpendicular to the joist. i dont know how to find out which way they go, maybe a stud finder? Im just a bit nervous about doing it.....any thoughts