Hmmm. I'm not in love with the idea of using driftwood that hasn't been properly treated. Too many problems can find their way into your tank. Although driftwood will eventually lower the pH of tank water, your problem is more likely one of hardness. I would filter through peat to lower the hardness as well as the pH.
I've a friend that breeds discus in KC. His water is liquid rock and he's invested in RO
units to provide the soft water.