We are buffing our tanks with that right now as I type (okay, my boyfriend is buffing and I am typing). My tank has a few good scratches and we are using 1500 grit on the deep ones with a firm finger and then going to Nouvus 3 with a ransom orbital electric polisher followed by the 2 and then a to 1. It's the hardest thing I've ever done. (okay, watched my boyfriend do :-)
The nouvus products can be used on the inside of the tank unlike other polishers.