| I would test 2 times a day just in case your surges happen in less than 24 hrs. My OPKs test different shades each day but when your surge is happening it's WAY darker than any other days. I surge for 48 hrs
This is my cycle of OPKs.
Day Night Temp
- + Low (The + is pretty dark lines)
+ + Low (Really dark lines)
+ - Low (+ is starting to fade and is gone by nighttime)
- - Low (Ovulation date since this is the last day my temps are low)
- - High (Ovulated, 1DPO) | 
Linear Mode
