I think the term 'organic' in this case- you mean 'soil'? There is organic hydro and the pH is in the range you gave for regular hydro. In soil, 6.4-6.8 is good, in soilless, 6.1-6.5 is more what you are after. Your goal is to get your RUNOFF to the correct pH, so you will have to check it regularly and adjust the nute solution going in, because it interacts with the soil as it goes through, and both pHs change.
Of course, if you re-pot frequently, into a soil or soilless that is at correct pH, you don't have to worry so much.