Why are you even testing yourself after taking one or two puffs? You're FOR SURE going to test positive, so it's a pretty redundant endeavor.

Do both brands have the same cut off value ? Are you sure of the expiry date of both ? Lightness of the line HAS NO RELATION TO ANYTHING. Faint line, thick line, kinda-thick line, kinda-not-so-thick line, kinda-faint line...whatever, it all means the exact same thing.