i recently cleaned (recharged) my k&n air filter and i cleaned the crap out of it, there was no dirt coming out after applying the spray treatment, followed all instructions as directed.
my end result however is not what i expected, the filter is supposed to be that pinkish red color, but mine was still a darkish maroon purple

Question:

is there an easy way to check if your air filter is being slightly restricted even in the smallest amount???
thanks