I'm just going to use a 32 gallon brute trash can for my ATO water storage. They're $30 at Lowes.
http://www.lowes.com/pd_46994-1097-FG863220+GRAY_0__?productId=3088677&Ntt=trash+can&pl=1¤tURL=%3FNtt%3Dtrash%2Bcan&facetInfo=#BVRRWidgetID
They have a 25 gallon that doesn't appear to come with a lid but it's $75