Find another adviser. Just because it's a hydro nutrient doesn't mean you lower the pH to hydro levels when growing in soil. Mix your nutrient solution and then adjust the pH. You change the pH once you add the nutrients. You might have pH'd your water to 6.5 but that's not what it is after mixing the nutes. As I recall from using that same nutrient years ago it dropped the pH significantly and was the only time I needed to use pH UP. It also gunked up my reservoirs, pumps, and lines with a dark sludge the color of the micro.
6.5 pH is fine for soil. The thing is that with good soil and minimal nutrients you won't need to worry about pH and your plants will get everything they need and do better than dumping a bunch of products on them or chasing pH.
Also, when you say you pH the water I'm assuming that's before adding nutrients. If not and you're talking about after adding the nutrients that would then be called a nutrient solution and should be referred to as such to avoid confusion. Water = water. Water with nutes added = nutrient solution.
You say you're in soil but your talking about hydroponic nutrient so I think your question is a little confusing?
