Ovulation cycle day #???


I'm confused. I'm a 29 day cycle and I had a very positive ovulation test marker on day 13 of cycle and negative on day 15, and I'm reading comments on here about ovulating as late as day 23 and I thought it was always like a little over 2 weeks into a cycle that u ovulate?? I get HEAVY EGGWHITE CM on days 11-15 and even till day 17 this past cycle. I travel a lot so timing is Very important to me cuz of planning my time with my guy. Help?