This is the 55 gal found at garage sale. It used to be a salt water tank. The previous owner put a lot of scratches in it. I'm hoping with it filled with water the interior scratches won't be as noticable. I've been trying to remove the salt scum with acrylic pad and vinegar, but not getting that good results. Should I fill it and let it soak with some vinegar added ??? If vinegar is left in for a while will it hurt the acrylic ??