T.I.B.E.T (The Incredibly Big Expensive Tank)

I just finished placing my order for the second to last piece of our automatic water change system; a HDPE Heavy Duty Horizontal Leg tank. Last purchases are actual plumbing parts, but I've learned my lesson about pre-ordering before I've figured out 100% what I'm trying to accomplish.

I have to say though the 55g garbage containers we've been using since 2004/2005 have done us very well. I want to re-purpose them but can't figure out how. I may just offer them up for sale at a really ...