You know ,and this is just me, I make sure my pH is in range, then again after my solution sits a bit before I put it in the tanks. When mixing, I get aeration through  vigorous shaking of my mixing containers. Stirring vigorously works the same. 

pH flexs all over the place, especially if you spend time watching it. My solution, nail it once and be sure its the same when I go to use it.

I found plants only get sensitive if they go over and lock out, then it's tough to drag them back. So up or down, you don't want it to range out of your soils pH range. Not all soils have the same range.