I think the joists in this house are actually thicker then ones I've seen in newer homes I'll have to look again but I highly doubt I would need a structural engineer to brace the floor in a house I'm only living in for a few years. I'm going to brace it up with columns and if the floor sags or something I will break the tank down if needed and store the tank until I buy my next house. When I start the hunt for the next house its going to have proper man cave where I can have a 300+ on concrete slab.