Yup, 24 hrs aerated seems to be the norm , from what i've noticed,,,and what i've been doing the last 10-15 yrs,,,after going from my previous home, where i mixed my salt in a 5 g bucket under the bath tub spigot,,doing the hand in the bucket for temp adjustment. luckily i didi not have that many fatalities or problems with my tanks,,,(I even did the de-chlor thing as i filled/mixed the water

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Doing the Rubbermaid 55 and 35 gallon g-can /containers now, aerated/heater in use/ and a powerhead for good measure now a days,,,, with the RO/DI above everything,,making it loads better than in the old days,,,,now all i gotta do is upsize /move the tanks downstairs , so my water changes will be a turn of a valve instead of lugging 2 -5 g buckets up the stairs now,,,,( i know, I know,,one day,,,,,anyone wanna tease me about my lack of progress on my basement finish/fish room-area, feel free to come on over and lend a hand LOL)
On the storage of RO/DI, i use my RO for drinking water for us humans, and for the dogs and parrots here, container in the frig for drinking,and a
clean milk jug on the counter for coffee/cooking etc.
I store my excess ro/di in the basement , filled from a number of 5 gallon containers i make my ro/di into,,,with clean plastic milk containers,,rinsed/bleached/dechlor'd after the moo juice is gone. I mark the containers i use for DI water, both 5g and milk containers,,leaving the unmarked for RO,,and mark all of them w/ the date i put them into service, since they tend to over time, develop pinhole leaks in them , so i can keep a eye on the older ones and rotate them out of service,,
I've been told , by a few very knowledgeable members here, that DI water, and RO to a point are "sponges" when i come to absorbing odors, and other bad things from the air, and possibly the containers they are stored in, The best storage container i was told was glass, but that's kind of not in the picture around here I do make a point of wrapping a damp cloth around the opening on the 5g containers when i 'm making DI,,,and capping the container as soon as it's filled, and when i fill the milk jugs, i fill them to the top as well as i can, and cap them immediately, for storage. I try not to make too much for storage, so my "stash" of water is not that excessive.
It's been said plain ro/di does not have that long of a "shelf life", and should not be kept unused that long.After the 24 hrs or so it takes to make one of my R-maid barrels full, i add my salt right then and turn on the heater/airstone/powerhead(actually turn them on as soon as the level gets high enuf to do so,,,)
It's also been said here, that mixed saltwater can be stored for a decent amount of time, provided it is kept aerated, and covered ,after the initial 24 hrs of mixing with the container uncovered, for off gassing/influxing of atmospheric .