My tank has these hard water deposits that have been there since I got the tank. It was free so I can't complain. When I got the tank I used everything I could find to try and get them off. CLR and vinegar did not work. They got pretty clean but you could still see them. No telling how long the people before me ran the tank with a low water level. I can see the stains when the water is on them also. It is kinda bugging me. Is it possible that the glass got etched by the minerals? Just curious if the tank can be cleaned successfully if I break it down. I did not try Muriatic acid though. That is the only other thing I could try. If I break it down I will be tempted to by a new tank. What do you think?