Faint OPK test lines

“The box test line” do you mean the control line? Your line needs to be as dark or darker. If you’re comparing to the picture on the box, some tests just don’t use a ton of dye so the line will appear kind of faded, that’s okay, your line just still needs to be as dark or darker.

Following, my ovulation day is supposed to be in two days and my second line is very very faint.. I’m on day 17 usually get a positive between 15-19