Cleaning inside glass of hard water stains

[Mbodell]

I have lines down the inside glass from the previous owner. They look like hard water residue lines. I didn't have time to try and clean it because of my move. Is there anyway to clean them off now with the tank full. I tried rubbing a paper towel over them but it didn't do anything. Is there anything safe I can try?

 

[Phyl]

Empty I would suggest vinegar. Full... apart from trying a ReefGadget I'm not sure what you would do!

 

[Mbodell]

I didn't think of trying a razor. I really have no idea either.

 

[arvin]

I used a credit card and it works quite good as well.

 

[Mbodell]

Not coming off with the razor. I guess I have to deal with it.