Guy,
I just wanted to comment on all the different ph numbers being thrown out. This is sort of where art meets science. People develop their own way of doing stuff. Different grow styles like RDWC vs Ebb & Flow, vs coco. All different and then add in different strains and phenos. So learn the concepts, not the numbers and learn to apply it yourself to your own grow. I spoke to a guy who had been growing 5 years and still having newbie problems...because he had become dependent on forum advice and forgot that he was supposed to think for himself. Just a little ramble...
JD