the scratch is on all over the glass,up-center-down.
somebody know how material or way to remove then?
the scatch is very small but i'have a lot of then
You need to get the polishing compound that telescope maker use to grind the lense. It is a Os-based compound, very fine and hard. Glass is very difficult to scratch, but once you accomplished that, it is very difficult to buff and polish.... lots of hard work ahead of you... good luck.
Go to a windshield replacement/glass specialist center. They should have the compound for buffing out the scratches. Just be carefull not to get it into your tank water. I wouldn't buff the inside without first emptying the tank completely. Do not put anything back into it until you've rinsed the tank out really good with a weak water/vinegar mixture. It takes alot of elbow grease to buff out the scratches but it can be done for most minor scratches.
Well, you are not dreaming, but dremel is too small for a flat surface, and you may end up with a depression on the glass, give it quit a bit of distortion when you view thru the glass.
I bought a tank once dirt cheap because it had a nasty looking outside scratch. When I set it up I put the scratched side to the wall where you don't see it. A scratch on the inside would get algae in it and be hard to get out though. If the scratches were deep, I'd just leave them. You would be removing a lot of material to get them out, it would seem to me. Be ok for surface scratches I guess.