You're in the same stage as me- seems to take forever, doesn't it? And the silly thing is, I can't remember the details of how it worked last time, just that this stage was the one that took the longest. I get up every morning thinking, it's got to have dropped in the night, and it hasn't.
Still, I do remember that it did work eventually last time, so no doubt it will work now, I've just got to have faith...actually, those bacteria probably don't care if I have faith or not as long as they get the right dose of ammonia. I overdosed at the beginning of this cycle, so that slowed things down a bit but at least now they are eating the ammonia, so things are moving, it's going to work...