...The issue I see is that the feet are not positioned under the upright portions of the table so as to transfer the weight directly to the floor...
I agree with Colin, and in my view, this is risky, very risky. Moreover, given the facts that- (1) the tank is only 48" long, while the table is 60", and (2) the only vertical supports that make direct contact with the floor are at the four corners of the table, there is going to be a whole lot of unsupported weight in the middle, this in a table that already seems to be sagging. With modifications and additional supports, this table might work, but as is, I wouldn't risk it. 75 gallons is an awful lot of water to spill on a floor. Good luck.