glass spots

[pepsimax]

I am having an issue. I bought a used 55 gallon tank and when i cleaned i notice the front glass had these spots on the inside almost like algea. I have used vinegar and razor blades but still nothing. any ideas?

 

[pepsimax]

pics

im gonna try and upload a pic so everyone can see what im talking about

 

[zarmalar]

Huh.... It looks like a pattern... Maybe that was their back of the tank where they had the background attached. I haven't the slightest idea how to get rid of it tho.

 

[pepsimax]

nah its actually on the front the back is solid black

 

[zarmalar]

No like maybe the front of your tank now was the back of their tank then. Unless of course you got the tank with the background painted on. Then my theory doesn't stand. Just a thought!