just fed my plants - one is three weeks into flower and the the other three are vegging till they are bigger. when i tested their ph after just giving them plain water, they were all in the 6.2 - 6.4 range. once i nute them, they plummet to 4 or lower. and the one in flower doesn't look too good. these are in soil, btw. If i get some ph up or whatever it's called, will that make the soil ph to high after awhile?