This morning I tested with smu on a first response early response.
Within the time limit I could see a extremely faint line. It's so faint I am unsure if it has colour, it looks slightly grey.
I have been googling all day and all I have come up with is it could be an evap line although it was in the time limit so I don't know.
I am 10 dpo. I will attach a few pics. One natural one tweaked.
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