A supremely controlled system would bring the best results im sure.
I believe just you answered your own question.
You will need to build an RO rez
so you will enough on hand for flushing your nutes.
I recommed you have at least twice the volume of your nutrient rez,
stored as RO only,
because there will be a day
when you need a lot of RO.
I'm sure you already have a good TDS meter
and change your filters often.
By removing the large amount of Calacium that is found in tapwater,
the pH will fall to about 5.0 when you add nutes.
Then you can use beneficial molecules
to bring the pH up.
First, I use Barricade(Potassium Silicate)
There are a lot of brands available.
Most Potassium Silicate(PS) is in liquid form,
and I use and eye dropper to apply it to my rez.
PS provides your plants with a nice healthy substance
that helps the cell remain rigid.
After I have Upped the pH a couple of times with Barricade,
I switch to General Hydroponics dry concentrate.
This stuff is a powder of Potassium Carbonate & Potassium Hydroxide.
These molecules are basically nuetral to the plant,
releasing ions
that increase the pH
and buffer the acidic condition caused by the nutrient salts.
I mix it with RO to make a solution,
and again, with a different eye dropper,
to apply it to the rez.
Once you do it a few times.
and you have kept a record of how many drops you added,
and how you prepared your carbonate/hydroxide solution,
you can buffer your rez in a few hours,
if you have the time to watch it all day,
right after a nute change.
Try not to panic if you overshoot your pH target,
give it a little time to see if it falls back into parameter.
Here is the ideal situation:
You flush your rez.
Add back 000 RO
Add nutrients and additives, minus Barricade.
You check the pH and it is 5.04
You add 3 drops of Barricade
and monitor the pH for ten minutes,
and it raises to 5.5
You add 2 more drops and the pH raises to 5.8(perfect top)
after two or three hours the pH is back to 5.5
and you add 3 drops and the pH raises to 5.9(not too bad)
and in a few hours you got stoned and let the pH fall to 5.1
no problem.
Now you add a couple of drops,
and the pH comes up to 5.8
(now we hope it is stable or starts to fall slow)
and it does, falling to 5.7
(wow that is great)
Sometimes it continues to fall
after a day or so,
and now you use the
GH pH up
to bring it to 5.8
(hopefully not too high)
because the pH could get stable,
and you don't want to be chasing it
with Up and Down.
Keep some records until you find that one magic combination
for your rez,
for your nutes
and your potassium molecules.
Mixing the three PS molecules
will bring stability to your nutes.
May the force be with you.
.