I only worry about the media PH when its a water grow, not sure why you would need to chek the root zone in soil or what you would do about ir if its off? Is there a root zone PH target chart on here that I dont know about or instructions on how to correct it? Never understood why growers check the run off PH either. I would think it would be a fairly complex report from a lab incoming and outgoing to find out what the plant is using and what it's not. They check my outgoing ever 3 months and its a through check, I am glad they dont check incoming, If you really want to know how the plant is doing check the SAP PH and the brix