How is everybody stacking these 500 gallon tanks? More specifically, how is the top tank supported? Do you modify the bottom one to support it or do you build a separate support structure for it?

Along the same lines where is everybody placing these things? I’m thinking about stacking them in the corner of the garage.

I’d be inclined to weld up a pretty heavy duty angle iron stand. Garage is good - close to heat loads is the goal. More insulation is better, so it would be nice to be able to frame in an enclosure and fill it with fiberglass.