Ovulation Sticks Question

Hi Everyone!

I’m still trying to figure out this TTC so I apologize if this is a newbie question. I’ve been using ovulation sticks to try and track. Is it normal for the line to be very faint most of the time, and then when the levels spike to suddenly be very dark? Last month I feel that’s what happened. I *should* be ovulating tomorrow according to the tracker, but the line remains faint. Does the hormone pre-ovulation gradually increase or does it suddenly increase, hence the much darker line suddenly one day?

Thank you! I hope that rambling made sense! 😂