Just a quick question: would you pH adjust your RODI *then* add Ca/Mg, or add the Ca/Mg *then* pH adjust?
I don't make any adjustments to the nutes until everything is mixed. No telling what the final adjustment needs to be until everything is in the mix, so I wait until everything is in the mix.
As a general rule, I haven't had to adjust mine at all. I just add everything to the RO water and it is within range every time. The only time I ever add pH up or down is if they've been feeding heavy and have lowered the PPM enough to affect pH. Even then it's rare I need to adjust, although I am only checking every 2~3 days.