New water needs

[Mr._Bond]

When storing new water, to be used in the future, is it necessary to have a pump in it circulating it? Also, can you put a lid on the container it's in (or will that trap gasses or anything else in there)?

[reiple]

I only need 5 gallons when I do water changes. However saltwater mixes come for 30-40 gallons. Here's what I do;
I mix it. When the SG matches my tank, I set aside 5 gallons and store the remaining in 5 gallons drinking water containers. Then seal them air tight and not exposed to light. A day before I will do water changes I open up one, aerate using an air stone and air pump then after 12-24 hours use it for my tank.
So far works well.