The soil is ph balanced; not the water. Adjusting the ph of the water does not effect the actual ph at the root zone. Runoff ph in soil tells you nothing useful. To adjust ph of soil:
To adjust the ph + up add D-lime
To adjust the ph - down add organic material like compost, pine needles, leaves, etc
You need a decent quality soil probe to measure ph at the root zone with accuracy. It is the activity of microbes in the compost breaking down organic material that makes a mix more or less acidic and that activity can change from one area to another in a container. When you recycle soil to reuse it you add compost and other amendments that typically drops the soil ph slightly acidic. Just letting it set for a month normalizes ph back to a proper range. It's pretty much automatic if the soil is properly limed and active with compost. That's why adjusting the water in a soil grow does nothing; it is the soil itself that sets ph. Of course in a hydro medium there are no ph buffers so then you need to adjust the water for proper absorption.
Absorption in natural soil occurs through fungal activity. Myco Fungi can be easily upset by high npk values resulting in what can resemble ph lockout. That's why just plain water always works best.
So no using ph up/down is not only not organic but also basically pointless in a soil grow. If after each run you simply add some D-lime along with ewc and let's say a fertilizer to your mix and let is sit for 30 days to recycle it you should not have any ph issues.