I ran into a buddy in town over the Holiday and we were discussing work. He does finance for a company that manufactures fire dept. equipment and through talking politics and work a discussion about working with the Chinese and quality came up and he said, "It's a real problem. We don't do business with them anymore. Your first order meets spec for a stainless steel alloy and the next order is some completely inferior alloy. You'd never know unless you checked."
My point is I would be very cautious filling and putting these tanks into service... IMO.
The Chinese are quite capable of producing top quality goods, but insuring the quality of any given batch can be challenging.
Large concerns that can build and staff their own production facilities have good control over quality.
2nd Tier concerns that may not own the foreign facility can still employ QA managers that answer to them, not the production facility owners. This too works pretty well
Below those two levels the situation changes. Often a buyer in the US seeking a foreign made item is dealing with a "Broker", but may not be fully aware that this is the case. The Broker has a range of contacts in China that produce the requested goods, but does not own the facilities, and may not be involved in QA. A US buyer places and order, and the Broker puts the request out for bid. The low bidder gets the job and the goods are produced. This 1st production facility may or may not be the low bidder for any reorders. I've had the experience of requesting samples, approving them, and finding after the 18-24 week lead time that the goods were markedly different from the samples. The reason is simple, the samples were provided by factory A, but factory B was the low bidder the day the Broker let the contract.
Low costs of production, but this comes at the price of not alway knowing *what* is going to be in the box when it finally arrives, and trying to trace back to the actual maker can be nearly impossible.
Add to that the real chances that agency certifications maybe counterfeit......
Tobin