This still troubles me,the tank sizes you use in the US,you seem to measure in actual air content,while we use the water content of a cylinder.LP-HP they seems to be in the 200-230bar range.
We only use 232 and 300+bar.
That would imo mean that a "standard AL80(sizewise) also could be a "bigger"tank.
Confuses the hell out of us too.
Part of the bad rep steel tanks took in the US comes from the + hydro rating we have here. And then the first non- plus rated Steel tanks needed that fancy fitting (DIN) that many dive shops did not have, and no regulators had. And the dive shops had compressors that shut themselves off at 3200 psi which left you with a short fill.
Boat diving is big business. Non standardized tanks don't fit snugly in the rigging on a boat, which is dangerous. Some captains simply will not allow anything that is not a standard size 80 on their boats, for the simple fact that anything but an 80 won't lock in securely. If it won't lock in securely, it can break feet. (Ask me how many toes I have had broken. No, don't. Diving with broken toes, in full foot fins, is just a fact of life. But it hurts like hell. I was always quick enough to avoid the arch being broken, but never quick enough to get all the toes out the way.)
So you have two things from way back making people lean against steel, and one current thing that sets the marketplace against steel.
Standard AL 80s are not the cheapest based on material cost, but they are far and away the cheapest based on cost amortized over volume. On some of the islands I lived on you could get an AL 80 for $90.00, and any other tank size cost at least $400.00 (and take forever to get), simply because they did not drop-ship a shipping container full of them, the way they did the AL 80s. When you live on islands shipping container economic realities really affect the price of most everything. If you buy what everyone else wants, you can spread the shipping cost over thousands of items.Even if you live somewhere where shipping costs are not the main fact of life that they are on islands, it's still far, far cheaper to get a container dropped off than to pay UPS by onesies and twosies.
Which brings back the 'no rust' point. The tanks were ordered unassembled, and left packed in the shipping container until sold. Steel tanks rust if left in that condition. Aluminum does not care.
(Where I lived, I could get an AL80 for $90 new, but a box of cereal cost $10.00. Shipping Air (which is most of what a box of cereal is, is expensive.) And the only milk was powdered milk, because paying to ship water is too expensive.)
