Trouble reading nitrates test
Hello. I have a lot of trouble reading my nitrates liquid test (API master test kit). Anything past 10 is so hard for me to tell the difference between the different reds. When I tested my water last night, I honestly couldn't tell if it was 15 or 50. The only way I can really make out any difference is if I hold the test tube up against the card, and look at the colors through the tube and try to find one that blends in the most.
Does anyone have any suggestions on how to better read the test? Indoors? Outdoors? Thank you for any help.
I have no idea what I'm doing!