Talked to one of my coworker, He said its pitted rust? He said I should just run the tank how it is and work on it next summer. Only should be worried if it starts leaking
Bad advice.
Rust never sleeps, and will continue. It needs to be 100% removed, or sealed over.
And when you have rust in the tank, all it takes is one granule, holding a float needle open, to lead to overflowing carbs.