Different Results with different brands?

Stephanie • 2 year old son pregnant with son #2

Twice this month, I have tested with two different OPK’s using the same urine sample and received different results. Each time, one was clearly positive while the other was clearly negative. A little confused? Which brands do you ladies use and/or feel is more reliable.

Top is CVS brand strips, bottom is clearblue (as you can see lol).