Glass cleaning? help

[Valum]

Ok so this is a problem I have found on my fresh system but glass is glass I suppose it's almost stained but can't feel anything with my fingernail any ideas?

 

[Valum]

 

[Nanorock1970]

Ok so this is a problem I have found on my fresh system but glass is glass I suppose it's almost stained but can't feel anything with my fingernail any ideas?

What have you tried cleaning it with
Just a magnet cleaner?

 

[...]

I cannot find what you trying to get, if its on the exterior of the tank, use some white vinegar and then a towel to dry it but if its on the inside, maybe get a blade or something to scrape it?

 

[vetteguy53081]

Looks like residue from glue or cement. I had a tank whereas the overflows were removed leaving a very similar effect. I tried to scrape it away but it felt like the glass itself and I could do nothing.
I wonder if a glass company ot tank manufacturer could suggest remedy?