I have stored water, I just pour in some CS. My stored water is Distilled as
I have a 1 gallon distiller. If and when I want to change it I
could distill it again and put new CS in. No set amount of CS in my water. I
suppose I should check the water as some has been on shelf for
2 years. I probably could go through and just add a couple ounces of new CS
to each jug. I am using large plastic jugs from juice. 
I am also using some large containers from pretzels (screw cap).
Bob