OK, I will keep this short and sweet.
If you have ever thought of buffing a scratch out of a glass aquarium, and been tempted to buy a kit like this - dont.
Either it doesn't work, or I lack the patience for it (and I spent 2 hours working on a 6 inch scratch tonight that was totally w/in the kits parameters to remove.)
I would show you before and after pics, but, honestly, I can't tell them apart. I made ZERO impact, and i would desperately like those two hours of my life, and the money i spent for the kit back.
don't do it. Buy a new tank.