@PadawanWarrior .. It really is something you don't have to worry about when you get it dialed in... you can concentrate on other things like environment, light PAR readings, your notes, what kind of wine you want with dinner tonight... It just makes your life easier as a grower. Especially if you have a direct soil probe that can read soil and liquid both. I can mix up my 55 gallon tank in about 5 min, and just by doing it over and over again with adding everything in milliliters, I rarely have to correct my mix. I don't stress about ~50 difference in PPM or a couple of tenths off on PH because all the plants are a little off anyway in their PH. Good news, is you have that 6.3-6.8 window to work with. But, as I have said before, I tend to overshoot it a little... like I'll get a reading of 7 fresh and wet, the next morning it will settle 6.5-6.6, and start gradually dropping as the soil dries out. By the time they are ready for a feeding, I'll get a 5.8-6.0 reading, and feed again at 7-7.3 , and they will be in that "window" to eat as the PH drops and soil dries out.