Here is a link to a really good PDF document on building a system from an IBC Tote:
IBC's of Aquaponics
These used food grade 275 gallon IBC's can be purchased for $100 at San Diego Drums and Totes in Lemon Grove. They originally contained bulk shipments of food like olives or honey etc., and were completely rinsed and cleaned before being put up for sale. I have several of them on the side of my house tied into my gutters for rain water collection.