I mixed about 25 gallons over a week ago and then did not end up doing a water change. Today I took the top off the brute can (not sealed, just covering it to keep out dust, the cats, etc), and aside from a small amount of surface scum, I did not notice anything unusual. No odor at all.
@Randy Holmes-Farley , if there were bacteria present, shouldn't something be off?
I understand you were citing general concerns, but after adding circulation and heating it to 77F, I'm going to test the Alk-Ca-Mg and will probably use it if they're not way off. Any thoughts on other things to look for?