not exactly windows, polishing scratch from glass

Hi I have recently aquired a nice fish tank but unfortunately after filling with water I have discovered a rather annoying scratch in the glass!

To make matters worse you can just about feel it with your finger nail too so it isn't a light surface scratch but I would say just beyond the threshold of being able to feel with nail.

I have looked at Cerium oxide and Jewelers rouge (Iron oxide?) but am worried that using these will leave distortion in the glass? Or would it as the glass will directly contact the water so the refractive index will be less than air? The other thing worth noting is it is a bow front of about 8mm thick glass but I can't see there being a structural issue with so little removed?

There is another product on the market which claims to remove scratches by moving glass molecules into the scratch and thus leaving a distortion free perfect polish but I can't find any way for an end user to get hold of this stuff.. unless I could take the tank to a specialist?

I also heard a 20% solution of hydrochloric acid can be used but not sure about that myself.

Any glaziers or other knowledgeable people here who can help me out?

There're plenty Glass Scratch Repair Kit companies out there, one of them here http://www.glassscratchrepair.co.uk/

Type in "glass scratch remover kit" in google for more info.

Depending how deep & where the scratch is and may show a ripple effect when the scratch is taken out

Thanks I am aware of those kits they are basically Jewlers rouge and I am sure would leave a magnified effect in my tank but I am basically seeing what options come up really.
I would love to know what lies behind these more advanced 'secret' techniques - I actually suspect acid then a light polish with rouge but could be wrong. LOL maybe they use t-cut who knows!

To keep the glass flat, the scratch need to be fill in then polished,

Copy & paste from my Glass forum, try it first on another sample glass to see if it works. Similar to car windscreen repairs kit so might be worth looking at that as well.

If you have a steady hand, and some patience, you can use a toothpick or pin, and dab some super glue in scratches. (Make sure you clean the scratch area first with alcohol.) If you make a mistake and have a little runover, it comes off with nail polish remover. I've done this on glass doors where there was a scratch from something hitting it. Could be worth a shot. Good luck!

Worth a read below,

http://www.fitchfamily.com/glass.html