If you really needed a quick and permanent fix, then you would've read my first post, done your research, and then realized you are doing too much work to get too little of a result.
Yes, clean your tank out.
Then seal it.
There are a bunch of brands, however, you should really stick to something like caswell or the por15 tank sealer.
The sealer takes 1 or 2 days to dry depending on temperature, and then the inside of your tank will never be rusty again because the sealer is a hardening coat on the inside.