Is my compressor doomed?

[FigureItOut]

I have a little 29 gallon 110 upright compressor that suits my needs. I've done my best to take care of it, breaking it in properly, maintaining oil and draining it regularly.
Unfortunately, the drain **** is not at the absolute bottom of tank and I just didn't notice until last week. I opened it and tilted the tank and was concerned to say the least to see about a quart of rusty-colored water drain out.
So my questions are: Is there anything I can do to repair and/or arrest the damage done? Is this actually a big deal? What should I have been doing to prevent it in the first place?

 

[nh_yota]

All compressor tanks rust on the inside because they are uncoated steel. How old is the compressor?

 

[FigureItOut]

All compressor tanks rust on the inside because they are uncoated steel. How old is the compressor?

About a year old.

 

[whyNick?]

It'll be fine.

 

[FigureItOut]

Am I to understand that a quart of thick rusty water isn't a problem, and other than tilting to drain it in the future there's nothing I need to do?

 

[The Cobbler]

....and other than tilting to drain it in the future there's nothing I need to do?

sometimes there's a dip tub from the drain to the bottom of the tank.