Pos on ovulation test, then the next day very negative

[Callie25]

I'm new to this... So admittedly it was using 2 different branded tests, but on my first day testing CD7 I had a strong positive line, same colour as the test line, on CD8 and CD9 it was very faint. I have short cycles (23 days) so this is definitely possible timing wise, but is this how it works?
Does it immediately go from really strong to nearly nothing?
TIA x

Yep, it can do. CD 7 is pretty early for the LH surge though.

I only have a 23 day cycle so I think it's possible? I'd been testing on CD 9/10 onwards and was getting nothing and couldn't work out why!