Pond Boss Forums AERATION Systems questions bottom cleanup

Pond Boss had an article on the dangers of aerating old ponds which is now archived at BassReource.com here:

aerating old ponds

It's interesting reading if not an exact answer to your question. There are no timetables mentioned, but it does cover "sniff tests" to determine if you are stirring up the anaerobic waste products you want to eliminate to make the pond ready for fish. If your pond has never been stocked you won't have to worry about the fishkill aspects.