I put mine in a big plastic tub and hydrate it all. I have kept the tub full for months without mold, mildew or any other problems with the lid on in the garage. I also buy it by the big combo brick so I hydrate a lot of it at one time. But I am using it for plants mostly so I always use a lot through the year. The large packs with the 4 bricks are thinner and easier to break up but that is a lot more than most herp/amphib keepers would use in a a couple years.