i pitched a batch of yeast last night, woke up this morning...and nothing was happening. Usually after the same duration in the past i have activity and krausen. Then i remembered that this time i pitched the yeast and then hit it with oxygen from a tank. I am thinking this might be less harmless to the yeast than say the same order would have been if using air as opposed to oxygen. I am thinking about pitching more yeast now if i don't see anything happen by this afternoon.