C.S.
I used them when I was trying to get prego this time (3rd baby) and started testing earlier in the month than I thought I would be ovulating and found that I ovulated a week earlier than I expected. We tried that day and the next and I got pregnant the first month. I think the line I showed was light pink. Also read the instructions carefully, they recommend taking the test during certain times of the day and also I think you should wait a certain amount of time since the last time you went to the bathroom. I never had much luck with the BBT, plus that tells you when you have already ovulated and it may be too late to get pregnant.