Hope that doesn't shock the yeast and get them to quit fermenting!
Hopefully not, I'm doing it slowly. Its down to about 74f from 81f right now, and it had 12 hours to do so. I cranked the temp down some more and it should continue to drop slowly till it gets to 68f.
Since my cooling is provided only by the ambient air in the chest freezer that should be a pretty gradual process. Airlock activity is about as slow as it was before I started turning the temp down.