I am a woman who can detect color! So why do I have such a problem seeing the difference between 10 and 20 nitrates on the liquid API nitrate test? I know men are often known to be a bit color blind, especially witb blues and greens and reds, oranges and yellows, so I don't see how in the world anyone can get an accurate reading with this nitrate test! The 10 does appear just a touch more orange-y than the 20, which is a touch redder, but still, when I hold the test tube up, it's so close.... Anyone else have this problem? I'd like to have an accurate reading!