# Can't remove the ultimate stain from used aquarium...



## SavemeDempsey (Apr 30, 2013)

I bought an old tank from gumtree was only $100, the ad read "4x2 for sale, a little bit dirty" It looked really good in the photo apart from the dirtyness had nice black edging and a toughened bottom pane looks to be built from a decent aquarium store. When I get their I noticed the silicone bead coming off the inside of the tank but also noticed it was a foot bigger then the ad read so I took the good with the bad and still handed over $100.

Now I get it home to clean it and strip the old silicone off and it seems like they had done a dodgy reseal and didnt take ALL the original silicone off just smeared new stuff over the top and the new stuff they smeared on looks like it was the wrong type of silicone aswell seeing as it justs peels straight off.

All the silicone off and now we get to this impossible stain which is basically over the entire inside of the tank, it looks to be some kind of calcium or lime buildup but I have tried vinegar, sugar soap, citrus cleaner, acetone, mineral turpentine and str8 up CLR.... (calcium, lime, rust remover) and it doesn't look like its even budged!!! I'm at the point now were im just going to leave the **** ultimate stain and just do the re-seal now and fill it up because it kind of goes away when its wet so it won't look to bad :roll: Any idea's on how to remove it would be great or idea's on weather you think the calcium might affect the new silicone seal... Cheers


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## ratbones86 (Jun 29, 2012)

Wanna post a picture of the stain so we can see it to give ya better idea?


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## SavemeDempsey (Apr 30, 2013)

My camera is busted atm but I have researched it and seen a few picture that look just like mine, it most likely has to be some kind of mineral buildup or etching. looks alot like this but mine is probably worse and covers the whole tank. http://www.bayoureefkeeping.com/topic/6 ... -aquarium/


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## ratbones86 (Jun 29, 2012)

did you try what he did?


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## SavemeDempsey (Apr 30, 2013)

yep i tried that today aswell, %100 oxalic acid, budged a bit and i re-sealed it today aswell so I will let you in a week if it leaks or not and also some photo's soon when the camera works


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## Iggy Newcastle (May 15, 2012)

You could try laying the tank on its side. Cover the stain in paper towels, and soak with vinegar. Allow it to sit for a day. Ensure the towels stay damp. Check and see if you can remove stain with a blade. It may take several days for the vinegar to do its job.


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## Allan01230 (May 23, 2013)

Try scraping the glass with a razor blade. I do this every week on my 65 to remove algae buildup. It never scratches the glass.


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## sikklid (May 21, 2013)

not sure if its non toxic, but have you ever used mr. clean magic erasers? they literally have never failed me with anything.

edit: wondering if you got it out btw


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## SavemeDempsey (Apr 30, 2013)

tried soaking it with vinegar paper towls for 24 hours aswell, tried magic erasers.... I think what seemed to work the best was the oxalic acid with superfine steelwool but I think I was actually polishing a layer of glass off so I think the glass is literally etched with this mineral deposit. I focused mainly on one side and make a bit of a difference after scrubbing for over an hour with a friend, so this will be the front and Im done with it now, letting the new silicone sit for a few more days and will fill it up with water hopefully cant see most of it us it dissapears when its wet... I also have read on the net that if my water is "soft" which I think it is it will actually absorb the minerals back from the glass and it apprently may just dissapear over time from being filled....


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## SavemeDempsey (Apr 30, 2013)

I don't think my Oscar will care about a few stains on the glass seeing as his in a 50L container atm  been in their for almost a week now...


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## triscuit (May 6, 2005)

Just make sure you rinse the tank extremely well to get all chemical residues out. And post a pic when you can... good luck!


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## SavemeDempsey (Apr 30, 2013)

let it sit for over 72 hours (recomended time for curing), right now doing a test fill and thorough rinse. Wish me luck


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## GTZ (Apr 21, 2010)

It's likely etched into the glass. I've run across this a few times with older tanks. Sorry to say but there's nothing you can do.


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