Dare- I'm going to try using opk's this cycle too. I'm only on cd6 so I won't be starting for several more days. It seemed like when I used then before I would get light lines and sometimes I'd get no line then out of nowhere I'd get a really dark pos. I would keep testing the the late afternoon don't drink too much before your test and hold your pee for several hours. If you don't get a pos test just follow your other signs. I like opk's because they tell u before u o and with the temping I can confirm o but if we didn't bd before that then I'm pretty much just out of luck. fx'd for a pos opk.