Welcome Ahorn! Unfortunately you can't go by the fading of opks to know when you've ovulated. The opks only measure the amount of LH in your system which can stay elevated while ovulation takes place.
Do you temp? Typically ovulation occurs 24-36 hours from the FIRST positive opk and can be as early as 12 hours or as late as 48 hours. Sometimes ovulation can be delayed, which happens quite a lot to us pink swayers! I would keep up BDing E4D well after you think you might have ovulated. I recommend BDing until CD21 or up until the latest you've ever ovulated, just in case.
FX and GL to you!
[emoji170]DS1[emoji1379], DS2[emoji602], DS3[emoji577][emoji170]
[emoji166]One last pink sway in 2016[emoji166]
My Ovulation Chart