As far as I know, the GO line does not require PHing. GO says they designed the product for use with tap water, but i still use RO or distilled. I didn't know that going into it, so my girls got ph up or down accordingly all the way through veg and did fine. the system seems to cover everything pretty well, but Mg and Ca seem to be lacking. Some epsom salts should take care of this deficiency, and you should be able to find OMRI certified orgranic salts if you really wanna stress organics. Good luck happy growing!