6.5 to 7.0 ph is for soil 5.8 to 6.2 ph is more suited to hydroponic applications although that seems a bit high for hydro but I'm not certain as I've no real experience with hydro. I've noticed alot of the products marketed online are targeted towards the hydroponic grower and that's the most likely reason the product your using is suggesting that ph level.
Yeah ph can be real critical because when the ph is off even though the nutrients may be there in the soil or whatever media you're using, the improper ph causes nute lock out and so the plant is getting what it needs to make that swelling happen.
Thanks, we appreciate the info. We had also had a farmer who used the apple vinegar. We do understand that the soil differ from hydro and agree with your ratios. We had a concern of using the ph down from the local hardware store because they had algecide? in it.