Ovulation test confusion

I am having serious confusion re: my ovulation cycle. The photo I posted is an ovulation test I just took. I am on CD16, which is my average day to ovulate. I have tested for ovulation since last Thursday and every test has essentially looked like this one. Test line almost identical to the control line, maybe a hair lighter. We've been BD every other day since CD8, so I'm not too worried about missing it, but what would cause so many unclear ovulation tests