Help with ovulation tests???

My glow app showed me that I was ovulating on the 25th, I decided to check with dollar store brand it showed me 2 lines, one is dark another one almost dark as the other line. And on the 26th I check again, but this time I checked with target brand up & up. Also showed almist the same results. I will post the photos of the tests. Purple is the first one, dollar store brand. The second kne is white target brand. Thanks ahead. And I have another question, how many days do woman ovulate? Thanks!