i use a magnetic cleaner and get sand inbetween on purpose to help scrub but never got any scratches. Thanks for the info, in the future I will avoid it. Sorry about the scratch :( .
Yea it really stinks because my tank is just the right size for the wall it is on and unless I special order one they dont make a five foot any more. I hope you dont have any. We didn't notice them right away but the algea shows up there first and is really hard to get out.