... well, I don't have AN's feed chart in front of me, so I don't know what full strength is with them per L,... but you're right, 2.1 EC is way too high!
I don't know what you "friend" is thinking about pushing water up to 10 pH?!?!
Absolutely wrong on all levels, don't even try this! Even with RO water, which has the buffering minerals (mainly CaCO3) removed, so that even small inputs can cause huge swings in pH,... Keep in mind, the pH scale is logarithmic, meaning going from, say, 6.0 to 7.0 is a 10x change, 6 to 8 is 100x,... Beside, getting your pH down is what's needed, making the water m ore alkaline is literally the opposite of what needs to be done,...
... I'm puzzled as to how your run-off is lower in ppm than inputs,...
As for testing run-off pH, it's not an accurate representation of what it is in-pot, but it at least shows a general trend,... Ultimate and first Mazar need to get lower pH in-pot,.. last Mazar is fine,...