Well is you do the math it comes out to approximately 2000 lbs. Depending on the structure of the home it may or may not. 1st thing to remember is if feasbale to place the tank across the joists and not along the joists. This obviously puts the weight on mulitple joist versus just 2. I have a 180 set up in that manner with no issue but every house is differnt.
if the floor and support is in decent shape you may also be able to just put a few floor support columns under them.
if you are still uncertain, have an architect check it out for you