Swilson, what is your water supply? Reason I ask is if it is city water you may have a bill through the roof. You may want to consider using a large plastic sheet instead of just draining-refilling-circulating etc. You can get a large plastic sheet and lay that on the pool. Fill on one side and drain off the other. The membrane keeps the new and old water separated and theoretically you can do a complete exchange without dropping the water level and risking damage to the liner if that's what you have. Sounds like you have a relatively large pool so I don't know if you would have to stick a couple sheets together to get the size. How you would do that I'm not sure. Duct tape may work for a while but maybe there is some kind of adhesive or solvent that would work and hold for the time needed.
Just some thoughts that have been proposed before.
Al