The thing is, when I take it in later in the day with dilute urine (nearly clear, but still yellowish), a faint line comes up (probably 20-50% intensity as that of the control) indicating I am negative.

BUT, when I take it in the morning, with concentrated, very yellow urine, the line does not come up.
The reason for this is because the dilution phenomena is only temporary - once the fluids you consume had all been urinated out, the bladder is replenished with fresh THCA-laden urine by the kidneys, and thus the donor resumes testing postive for THC.

I have heard that vitamin B2 helps make the urine appear less dilute than it is, but I do not know much about it specifically.
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