I was just reading through some older posts and saw where someone mentioned going outside with your back to the sun to test your CYA. My TF100 kit doesn't mention this. I normally do the test in my kitchen beside the sink. Should I test CYA outside? If so, that might be the reason I keep getting slightly "low" results. It may not matter at all, but thought I'd ask those who know here, just to make sure I'm doing it correctly.