Hey there.

I have never had a positive OPK, testing at all times of the day, even though through charting of other symptoms I know that I O on day 20, I can never ever produce the second line! If you have other symptoms, like your ferning, I wouldn't be inclined to worry too much about it. But try the other brand, that's a great idea.

Maybe I'm just an outlier. We can start a club if you like