Maq, the bottom strip is considered positive. And yes you're right that the test line must be as dark or even darker than the control line to be considered bingo. What I tested today just signifies that O is on its way. Not sure if everytime the test line will appear as afterall, I only start opk from CD14/15. But to some truth, from CD14/15 my opk does show line already. Just that it's super duper faint but slowly gets darker till about cd16-18 when I will get the darkest.