If you’re using Advanced Nutrients you should forget about measuring the pH, it is no needed. My grows go fine since I stopped to measure it …
With pH Perfect Technology, you’ll never have to worry about pH levels again! As long as your water falls between 4.5 and 8.5 pH (which is pretty much everyone’s water), this technology adjusts your pH and keeps it buffered throughout the plants entire growth cycle.
You should water according to the size of the plant, not the pot, no need to wait for a runoff, overwatering is a bigger issue than having them a little thirsty …