My husband and I have been trying to conceive for about 3 months now and I just started using ovulation tests. From my understanding, the test line must match the control or it must be darker. I test a couple times a day and have had a positive the last 2 days (the test matches the control). This afternoon, my test was MUCH DARKER than the control. So I thought this was probably the accurate day of my ovulation (is it normal to have ovulation at 16 CD?). However, when I tested just now, the test was much more faint. Is that normal to have a very positive test and then a few hours later have a negative test (I hadn't urinated for 4hrs before the tests)? I'm new to this and I'm trying to accurately pinpoint my ovulation day. It's been harder to try to conceive since my husband is in the military and has been gone a lot the last few months. Any advice would be helpful! Thank you!