Clearblue Digital vs Wondfo LH tests strips.

Me

I’ve been testing with both to make sure I catch my most fertile days.

This morning I got my first flashing smiley meaning “high fertility”. So now I’m testing once in the morning with FMU and once in the early evening.

Why does my digital say high fertility but my cheapie LH strip is only a faint line?

Also, I’m on CD 19. First cycle after stopping the pill.

Edit to add; the directions in the Clearblue digital say to test with FMU and again later in the day after holding for 4 hours if during high fertility.