That won't get you anywhere. They specifically exclude any sort of property damage from their warranty. This would turn into a legal battle exceeding the cost of the tank, and you'd still end up losing:
and
Just because they state things in their warranty does not make it necessarily legal and binding. My old company used to have things in their terms and conditions that wouldn't have held up in court.
Engineering wise, they are certainly libel for doing their due engineering diligance before producing a product and shipping it out for use. If they can not prove that, and a tank breaks and harms someone, the company could be found responsible.
Have you filed with your credit card? You just need to say that it was not what you paid for, and tell them that you are more than willing to send the product back to the manufacturer in the condition it was received.
And go talk with a lawyer.
If it was a $100 75 gallon tank, I'd say suck it up and take it as a loss.....But this is ridiculous. It's thousands of dollars. And you paid money to get a cadillac of a tank.