K. Been trying to figure out wtf these are. I've been doing research, and it looks like nothing else i can find. It doesn't look like crazing, they're not scratches, so what could these be?!!! I'm thinking MAYBE some kind of chemical damage? They're in a weird pattern. They have a VERY VERY slight texture, 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(stuff u see in the corners is dirt), or on seams, so structure of tank seems fine. But not knowing is bothering me :x . Top pic is what u see when normally looking at the tank. Then when u get the right angle, u see these things. Pic 3 shows the acrylic panel looking from top down. Sorry the pics r upside down, it was only angle i could get the marks to show up. I'm wondering if I should try to get them out or just leave them ...