K. Been trying to figure out wtf these are. I've been doing research, and it looks like nothing else i can find. It's not crazing, they're not scratches, so what could these be?!!! I'm thinking MAYBE some kind of chemical damage? They have a VERY VERY slight texture, are on the outside, and aren't very deep. Without flash u can barely see them. I probably don't even need to do anything. Its not on edges, so structure of tank is fine. But not knowing is bothering me Top pic is what u see when normally looking at the tank. Then when u get the right angle, u see these things. the seams are in perfect condition. Pic 3 shows the acrylic panel looking from top. Sorry they're upside down, it was only angle i could get them to show up