The Black Soil i use is a bagged soil that's a mix of topsoil, and composted materials, and a little black peat. I mix it with 30% coco coir. Then its a good base for either organics or feeding via Megacrop, etc. You can run higher PH this way and pretty much eliminate PH issues. I PH the Mega to 6.5 and have run this way for three grows now, not even one little sign of PH related problems. And the soil not only buffers, it retains nutrients better than any medium. plants not in auto pots are being feed only twice a week with great results.
I use an organic top soil, mixed with 1 part each by volume of soil, compost, and perlite. Not sure what @pop22 is using but it’s a mixture of 70/30 soil/coco. The important thing is that you are using some form of dirt to help buffer those nutrients.