PH can definitely be experimented with. TBS... I loved Sub and CPW's take on this subject ! I've grown a shitload strains maybe 200 plus, and honestly I never really tried to match a strain to a certain PH . I would tend to think that Cannabis needs it's PH to be within a certain range, and not that specific, to where it would matter. That is just my opinion . I almost forgot, your waters PH is important, but like SUB mentioned, the PH of your substrate is just as or more important. It can be a balancing act between the two.