Do not move an aquarium that contains water, sand, or rocks. The added weight will not only cause the tank to be far too heavy to move, creating dangerous conditions in the process, but doing so will also potentially damage the aquarium. The bottom pane of glass or acrylic will pull away from the rest of the aquarium, damaging silicone and seams. This will likely cause a leak in the aquarium, which can only be fixed by removing all of the silicone and replacing it. If you must move an aquarium, please drain it completely and remove all of its contents. Redoing the rock structure might be a pain, but it beats having to reseal an aquarium.