So鈥hat you’re saying is that you have some corrosion on the pole tips, some sort of discoloration or oxidation?
To be honest, my reaction is: Well, yeah. Humidity? Salt? Four weeks? The thing is, whatever is happening to the poles also is happening to the fabric, albeit invisibly. Tents just don’t last forever, and you’ve probably aged yours by a factor of four years or so.
What to do? Not much, really. Almost all poles are made from an aluminum alloy that is anodized to reduce corrosion. So there’s not much to be gained by shopping for different poles. You could paint the pole ends with a spar varnish of some sort (Varathane Exterior Polyurethane, for instance). My belief is that it will peel off in time, but it will give you decent protection until it does.
That said, I worry more about the fabric, which is going to fail long before the poles. Try to keep the tent out of the sun as much as you can鈥擴V radiation just KILLS fabric. Whenever you can, give the tent a rinse in fresh water鈥攑oles too. Then let it all air dry.