Used tank, VERY stained / How to clean??

[JK47]

Just picked up a used 55 gallon. It's obviously older since it's half inch thick/glass. It's very stained (was formerly SW) photos below. What is the best method for removing this stuff? It's really hard to scrub off. Any suggestions?

Will be used for a brackish mudskipper species tank.

 

[Nicksplosion]

vinegar and a razor blade

 

[Guerillah]

I do this on my car.. might work on your tank lol
http://www.valvoline.com/carcare/articleviewer.asp?pg=ccr20020801hw

 

[JK47]

vinegar and a razor blade

Any specific volume of vineger per water or just pure vinegar alone? I have read that before but never tried it.

 

[radioaktiv]

grey bottle CLR

 

[JK47]

grey bottle CLR

CLR? That's not a bad idea. I don't have any on hand but do have some "LimeAway" maybe that will work. I'm going to go try it on the lid. Will let you know. Thanks!

 

[radioaktiv]

CLR is biodegradeable
im not sure about limeaway :/

be sure and check it out

and if you go buy CLR make sure to get the grey bottle. the yellow bottle has foaming agents that wouldnt be so great in your situation.