Do you have a example of the plumbing? I have no clue when it comes to RODI in one and another is mixed. Not sure how it works.
When I did a water storage setup (I didn’t have awc) I had an indoor utility closet with two commercial 50g brutes
Gray was rodi and room temp
Blue was 1.026 sw and had a heater and a BIG powerhead in it. When the sw got low I would refill it from my rodi and dump the salt in and let the powerhead continuously keep it mixed. I’d wait 24+ hours before using it.
I figure if I needed to ever do a large water change then it’s heated and mixed and ready to go in the tank