There is a big difference between cooking something acidic in something reactive like CI or aluminum and storing it overnight in the referigerator in CI or aluminum.
When it comes to CI - the pot will season and become "nonreactive" over time - but the lid usually does not. Put the lid on - stick it in the refer - condensation will forn on the lid and drip back down into the pot.
One trick - after the DO has cooled - put a layer of heavy-duty Saran wrap over the top of the pot - to seperate it from the lid. This way, the condensation will form on the saran wrap, not the reactive lid.
Or - you could just transfer your stuff to something non-reactive before storing in the fridge.
Things with tomatoes will stain many soft plastics and leave them not only stained but feeling "greasy" - look for storage containers made from glass, ceramic or made from polycarbonate (a hard clear) plastic. I use polycarbonate storage containers for the local kitchen supply store and don't have a problem.
"It ain't what you don't know that gets you in trouble. It's what you know for sure that just ain't so." - Mark Twain