Fear of falling through floor! Real or Not?

[Reefmaster]

i vote "good reason for concern". depends on alot of things, dimension, spacing and span of floor joist, location of tank relative to load bearing walls, whether you have a grand piano in the same open room 15 ft away.
placing tank near an outside or load bearing wall and perpendicular to floor joist will prob reduce the concern. otherwise beef it up a bit.
shane