I have an aquarium that is probably around 10 years old (bought new). The glass seems excessively scratched up. I realize some scratches are probably from the gravel or movement of rocks over the years, but lots of them are horizontal lines -- can razor blades scratch the glass? Is it just getting old? Also, the seams, or plastic adhesive, in the corners is coming off -- is this a problem? I'm worried if the scratches might become crackes. I am mostly noticing this in the front glass.