API Master Kit, how to use the colour chart correctly?
4 months into my first tank and I still don't think I use the colour chart correctly... At least I am not sure if I am or not (lost instructions
So for example I want to test my nitrates, I first did a test on my tap water and it came up showing 0, clearly yellow in colour.
I test my tank and I get an orange, problem is I am not sure whether I am looking at 10ppm or 30ppm or somewhere in between.
There is no natural sun light in the room at all, normal light fixtures. Do I hold the card up to the light with the card separating myself from the light or with me separating the light from the card.
Also, do I put the test tube touching the white on the card or like a bit away from the card but still in front of the white portion?
Doing these things results in lighter or darker shades of orange which is confusing :s