I also notice that I only got full ferning for about 12 hours, and then it would start to disappear, so when I started to get partial ferning, I would use the MB morning and night for the next few days and usually would see full ferning only the once in that time. Eg if I had full ferning in the morning, it would have settled back into partial ferning by the evening. If you're seeing partial ferning, you're getting close, but you may miss the full ferning if you're only using it once a day.

Well, that's how it was for me anyway!