[zpyro]

Why would you presoak the soil? FF says the soil is balanced at 6.3-6.8, I don't think you should have to do anything but water it with pH'd water.

A higher/lower pH doesn't necessarily mean it will make the roots grow any differently. The medium/water needs to be in that pH range because its in that range that the plant can best absorb nutrients. Were I not on my phone now id link a graph that shows the different nutrient uptake rates for the range of pH, but I'm sure a quick search will find it.