Not sure which brand you use. I've been using a product (unsure of name can look it up later) that gives me faint lines before a positive one. So I can normally tell when its about to go positive. This brand state that a positive result indicates that Ovulation will happen in the next 12-24 hours depending on when you tested. And after that I will have negative tests. Im not sure if this helps at all.
You usually only get one strong positive and it can last just hours so you can get a faint line in the morning, a strong positive in the afternoon and then a faint line again that night. That's why I usually test 3x per day the few days before I expect ovulation, as it's so easy to miss the + otherwise. I usually get very faint lines in the days leading up to the +opk as well.