I agree with EmilyB, concentrate on the big tank, and leave the carpet issue for when you move out of that house. You 've got to refill that tank - hopefully you can do it over the course of a few days without too much trauma to the inhabitants.
Even with 3/4 of the water out, there's no way to move a big tank in short order, without removing it. It will still be very heavy as you say, and not much water should seep underneath, as the carpet and underlay will be in serious compression.
Chin up, Trevor - you'll get through this. It's your First Flood Story!
