Ovulation test question - what do you count as a surge?

I have been testing using ovulation strips from the start of my fertile period, and no matter whether I go without water or use fmu, it has come up negative. According to my glow stats I should have ovulated yesterday, however today i did a strip and the test line went from dark pink (positive) fading to a lighter pink (negative). I wasn't sure whether a partial positive counted with the strips, or whether the entire test bar has to be dark pink? Unfortunately my phone is broken so I can't take a picture!