Ph range for soil is from 6.3-6.8. I make sure my watering solution is at 6.5 before I feed it to my girls. I buffer my soil with a little lime to control the ph of my soil before I even pot them. I premix my soil recipe approx 3 weeks prior to planting or transplanting to allow the lime enough time to do it's thing. I never have any issues with soil being out-of-wack.
Just how I do it. Not saying it's right or wrong, but I never have any problems (knock on wood).