I had been using a 25G rubbermaid container to mix SW for water changes. After a month, I could feel the bottom of it getting kind of rough, and after a few more, I found stuff floating at the top of the water. I later realized that the SW was slowly eating away at the plastic, which was what was floating on the water. So I stopped using that, and am holding off on water changes until I can get a desirable barrel. Just putting it out there to any reefer that thinks a garbage can is a good idea for storing water; it's not.