The roller idea seems to be a real bad idea , even if you could get it to work without taking up too much of the vertical space in the lower area of your stand . Consider that a gallon of water weigh roughly 8.3 pounds . Times 72 = 597 pounds . Not counting the weight of the tank plus substrate/hardscape . Assuming your rollers work ,and you're physically able to roll the tank out a bit from under the stand , you now have all , or part ,of that nearly 700 pounds trying to tip over your stand . Might be a lot of work to achieve a not wholly satisfactory result . If you've got room , go for a separate stand. Or a smaller tank .