Opk confusion

[user000]

Anyone explain this? I bought two
Different packs of Clear blue purple Ovulation tests

One was solid smiley yesterday

So today I used the other reader and it shows a blank circle

Any idea why?

I have light cramps
Today

Why did you use two different readers?

The first time you test it always shows a black circle.
it intakes your hormone levels.
Then id sees if they are increasing.
It also depends how concentrated your pee is, you have to test after avoiding the bathroom 4-5 hours, it needs to be really concentrated to be accurate.

blank* circle

New digital readers are always a blank circle on the first go I think?

Got it thank you
Now I've gone solid to flashing any ideas?!