OPK - Wondfo

Kelly • Had my daughter on July 5, 2016 ☀️ and my son on October 23, 2017 🎃
I've been tracking my ovulation for the past few months, and this is the cycle I've started monitoring every day. Anyways, I. can't seem to ever get a true positive! I've read it's not uncommon with this brand.. 
I've posted the picture with my strongest result below. It began fading again after that. Has anyone else had this problem?