My Solution
I had the exact same problem.
I built a rather large centrifuge and mounted the tank in it. Spinning at approximately 6000 rpms settled it in about 23 minutes. Of course, I removed the fish first. Just so you know, I removed about 20% of the water first, so it wouldn't splash out during spin-up and spin-down.
If anyone wants blueprints, I could try and draw them up.