What is the circle inside Catalina AL80?

[Swamp_monster]

I just got this tank back from hydro which it passed. I decided to look inside the tank, I noticed this circle inside the tanks - looks like some sort of machine mark or maybe from drying. I am not worried about since it already passed the hydro and they vip it before they hydro it. Just wondering what this mark is. All my other tanks are Luxfer and they do not have that mark. Anyone know? This will not cause any issues on the next VIP?

 

[Johnoly]

Just a guess on the small dark circle at the very center....Maybe a carbon or dirt stain from a compressor fill? Your shop should be able to clean/tumble it out if you want.

 

[Superlyte27]

It’s the way the tank is made. You can’t tumble it away.