Opinions vary by quite a lot on washing, but I use 20 minutes, without hypo clear.

To expand your tank collection, these food canisters work very well with 4x5 single sheet hangers, they are readily available from kitchen stuff stores; http://www.oxo.com/p-442-pop-contain...-15-quart.aspx

Note that these "tanks" are shorter than the hangers by 1/8 inch or so, thus the hangers don't actually hang at the edges, but they are a good fit in all other respects. Plus you get a sealed lid if you want it.