Well, keeping in mind I'm using the pH perfect at half strength with RO water, I checked the pH just out of curiosity after adding the nutrients. I didn't add anything because you aren't supposed to, since it supposedly has the magical buffers in it that allow it to fluctuate within the different uptake ranges... however before nutrients, pH was 6.7 and immediately after being added pH was 5.7. The coloring on the leaves started yesterday.