U could try testing twice a day. I started doing that my second month of using opks cuz I never saw a surge and picked it up that second month. I think I must have had a short window of "surge" time. So I tested at 6am and 2pm just to make sure I wasn't going to miss it. I think I read somewhere that a surge can last for only 12 hrs so if only testing once a day u won't actually pick it up in an opk?