Sherry,

You might be a candidate for the "plastic sheet method" that's been mentioned on this forum several times but I'm not sure anyone has actually tried it.

Basically, buy enough 4 mil poly sheeting to make a 36' dia circle. (width of your pool plus 4' on each side for the depth. You'll have to tape smaller pieces together (duct tape) to form this piece.

Lay the piece on top of your pool and begin draining. As the water goes down, add the new fill water on top of the plastic at the same rate you are draining the old water from underneath.

The plastic separates the two bodies of water (perhaps not perfectly, but close enough) and, when it reaches the bottom, you have done a complete refil without reducing the total volume in your pool at any time.

Again, it's a great idea and I see no reason why it wouldn't work.....just don't think anyone on the forum has actually done it. If they have, maybe they'll chime in and report results.