p.h

Hello all, i have a general question about the water i am using. I get water from the corner stores purified water station that says it filters the water through RO. When i ph and test its ppm's i get a ph of 5.6-6 and 20-23ppm. Granted that i raise the ph a bit, would i also need to add...

Is this right? im so confused i dont know if its because im baked lol. I water my girls at 6.8-7 and the run off is PH at 5.0???

So my filtered tap water is PH'D at 6.5-7 And when i add 1.5 ML of general hydroponics micro flora it goes to 7 So I've been testing the run off and the past couple of waters runoff been 5.5 - 6 So im wondering does nutrients make the soil acidic over time? and what can i do to raise this...