I use Waterbricks for my water storage to help mitigate any unforeseen incidents that result in my local water supply being interrupted for any reason. I posted in one of the Discord servers that I lurk on about using chlorine dioxide tablets for treating stored water and Tim replied about bleach:
Cheapest household bleach, put in 1/2 cup add some water, close and slosh all over like a madman. let sit for 5 minutes you are now sterilized inside. I also setup a spray bottle with the same solution to hit the opening and lids just before filling and fill then close.
I thought that half a cup was maybe too much so I opted for a couple glugs from the jug, maybe 1/4 cup or so but otherwise I did it as described. The rest of the waterbricks will have the same treatment when the time comes for rotation.