a few questions about buying used acrylic tanks?

so ive only owned glass tanks, and need a little info on what to look for in a used acrylic tank.


how deep can scratches be before they cant be buffed out or effect the strength of the acrylic panel?

i understand what crazing is but not how much is acceptable or if all of it is a red flag to not buy a tank.
any other things i should look out for when evaluating a used tank?

Ive been looking at used acrylic tanks myself. Another factor Ive considered is the wall thickness. While I notice many large tanks get away with 1/2", I really would be looking for at least a 3/4". Just for my own peace of mind.

I just bought my first acrylic tank. It has a few scratches and some crazing but looks good overall. I let you know how it all goes.

My 400 gal only has 1/4"acrylic.

I just bought a 360g walk around tank that's only 1/2 which is the same as the 75g sump.