Guys,
I fell of the horse before I was able to get started lol Work, life, blah blah. Any way. I picked up where i left off again. I am trying to set everything up in my room for routine maintenance. I would like to buy a garbage can and stick it in my closet. I will throw ro/di water or dechlorinated tap(I know this isnt recommended becuase of phosphates and potential algae issues, but most get by on it) in the can and put the salt mix in. Once I am ready for the water change (and the params such as ph, temp, and salinity are close to my display tank) I will throw a pump in and wahlah. Does it matter how long this water is in the can in my closet?? A lid will be on it to protect it from contaminants and dust and stuff. And i know to make sure i start my prep for water changes at least a day before. Trying to get on the wagon here fellas.

I would say just make sure your garbage can is fully cured. There is a way to clean it and make sure the plastic contaimenents are all gone. a little bleach first....then let saltwater sit in it for a weak or so...then drain it..move it to where you want to keep it and there you go....fully uncontaminated trash can. I wouldnt hold the water longer than 6 months without using it....I wouldnt see why it would go bad. Theres nothing in it. Just make sure you keep it moving....with a power head.

if it is ro/di water it shouldnt go bad but tap water will....... i know it doesn't make much sense but it has happend to me a few times with tapwater, sometimes afeter like a week it starts to smell like sewer water

nothing wrong with your theory, my only question is how big is your tank............do you need a trash cans worth of water on hand at all times?? i use a 5 gallon tot with a locking lid from wally world for my water {small tank though} and i have water running at all times ......so it can be in there for weeks at a time sometimes