... the foaming was bothering me for reasons you mention, was thinking about a barrier, but I like your idea, air moving all around is good. Funny what you say about neoprene, many fabricators recommend resting the tank on neoprene, I have not seen any with the warning of pure neoprene. My tank is triangle shape, it (sort of) follows the shape of the hull, so it is anything but flat where it is located. Perhaps there are already stringers of some sort in place, we'll see.

The label on my tank says #5062 aluminum, have not actually measured it, the .09" is a number given to me by the builder, Florida Marine Tanks.

Thanks Mark, cheers, John