i have 4 ea 1000 gal tanks here on the farm, each on a stand 6' off the ground. also have a 1000 gal tank on a trailer that is towed to tractors/combines when they are in fields too far from the fixed tanks. i have a larger tanker truck refill them when low or less than half full. it has been my experience that all metal tanks rust over time. one of my tanks is over 20 years old, and still going strong. each tank has a filter right off the tank (at the beginning of the hose line), which is changed every other time the tank is topped off. keep the filters changed and when you mount your tank (on a stand or a trailer) slope the filter/hose end up a few degrees so the sediment settle on the other end from the filter. as you probably know, clean, properly functioning filters are key to clean fuel. filters are cheap when compared to diesel pumps, injectors, etc.
