I want to raise my hot tub off the ground when I install it. I am thinking I would basically build a 10' X 10' box that is about 1'6" high. I would make the sides of the box out of either garden ties or 6" X 6" PT posts. I would then fill the middle with 3/4 down and pack it with a tamper. Then a layer of sand, and then top it off with a bunch of pavers or sidewalk flagstones. Does this sound like it would hold up to a 8' X 8' hot tub filled with water?