I'm finding DWC to be easier then Promix, plus no messy runoff to fool with is a plus. If something goes south, you can fix it with a res change. If you burn them, flushing is a breeze. When you run into problems with soil or Promix it takes much longer to correct it. Also compost tea does wonders for the roots. Helps prevent and cure root slime/rot. As far as pH for DWC, 5.5-6.3 is what I try to maintain.