I just tested my pH with a "Red Sea" pH & Alk kit and looked at the sample using the fluorescent sump light. The sample is GREEN. It isn't the olive green that represents 8.0 on the scale, it is a sickly lighter green that doesn't even show on the color chart.
So I walk the sample into the kitchen and, under the incandescent lighting, it's a nice purple around 8.2 - 8.4 range.
For the sake of science,
I wander around the house comparing different fluorescents , from 3k to 6.5k and they all produce a green color sample.
All the incandescent lamps are showing the sample as being purple.
So I check the instruction sheet, to see if they mention to use a particular light source, and they just say to "hold the sample up in front of a white background"!
I could see someone dumping a whole lot of chemicals into what was (up to that point) balanced water just because they held the sample up to a fluorescent light and figured there had to be a problem.
