It depends upon the instructions for the test and I'm not exactly sure what kind of test you are taking...for example a test like this says: "NEGATIVE: Two lines appear. A colored line appears in the Control Region (C) and a colored line appears in the Test Region (T). A result should be considered negative whenever there is even a faint line - shades of colored lines in the T Region may vary. Negative means that the concentrations in the urine sample are below the designated cut-off levels for a particular drug tested."

So even if it is a very faint line you should be fine. Your Day 30 test looks especially good.