Hello, i just got my Milwaukee SMS122, test the calibration solution. it got reading of PH7.0, then i put it into my fish tank, it said PH 8.1, but what do i need to do make the water to lower PH. right now i don't have co2 put into yet. but i will put co2 by tommorow? or will most plant will grow on PH8.0 water?