Wonfo vs. Clearblue?

[Iwonderwhen]

It's my first time using both testers and I am lost.
I saw a smiley face from Clearblue on March 10. (smiley was gone on 11th)
Wonfo was dark and stayed dark until March 12th.

Did I ovulate on the 10th or the 12th?

 

[amariee]

This is what I found on the clearblue brand


The Clearblue® Digital Ovulation Test detects the rise of the ovulation hormone LH 24-36 hours prior to ovulation and identifies the 2 best days to conceive in a given cycle. Having sex during these 2 days gives you your best chance of conceiving.

So wondfo just detected the entire surge. Did you at least bd on the 10th and 11th??