Paul, what have you done for reinforcing the floor? With that much weight, you really should be pouring about 6, 2 ft piers. It won't take much settling from a long dry summer to cause your floor to start cracking and enentually sinking with that much weight on it. If it were a solid object, you may be ok, but with a liquid object, that shifts it's weight, even if slightly, i would go for the better safe than sorry approach on this one. It's not a big deal at all to pour some support piers, then you know it will be safe. I have worked on a lot of homes in the OKC area, and not many of them don't have a few cracks in the floor. One crack within a few feet under that monster, and you could come home to a MAJOR disaster one day.
They sell the cardboard tubes you use to pours piers at HD cheap. It just takes minutes to saw out a square hole in the slab and dig out the sand 2ft deep. The slab will only be between 2 and 4 inches thick, depending on how broke the builder was the week your slab was poured. This would also make a perfect opportunity to run a floor drain that could insure this thing never floods your house.