ph normally becomes a problem with overfeeding and not enuff water changes this is where some pet shops make money by giving them a band aid and not a prevention. we must remeber there are a lot of ppl still out there that believe fishkeeping is as simple as a golfish bowl fill with water and plonk a fish in. so when the fish starts dying , they go 2 the lfs who say have u tested the ph , no how do i do that, u buy a test kit it should be neutral. now they will either find its slightly alkalne in chch or acid , so back to lfs buy ph up or down and kill another fish due to changing the ph 2 rapidly. all that really needs to be said is, do u have ane calcium based roocks if the ph is high(assuming the ph test kit) or try feeding your fish less and the magical statement do a waterchange i admit sometimes there will be a case where its something out of the ordinary causing ph readings but generaly not