just store it in a box with a lid away from sunlight and it will be ok. I get my water from the ocean and I store it in the box I get the water in. I keep it in the garage and when I do water changes I just stir it and cuck it in the aquarium. Works great. There is some sientific explanation as to why you can store salt water for periods of time and the salt has something to do with it. DON'T grt a power head and a heater in there, thats a waste of money!