Hello from Indiana, I just bought a 45 gallon corner tank/stand saltwater setup from Craigslist, but I just can't get it clean. I was able to get the easy stuff cleaned, but I can't clean the hard water stain in the glass. I've tried straight vinegar, 50-50 vinegar/water, vinegar/water/salt, I've tried the Bar Friends Cleaner(that helped little, but not much), 1500grit wet/dry sandpaper(that helped little, but not much), and a lot of elbow power, and used a razor blade during each way I tried to clean the glass.. I do not want to use any chemicals. Any thoughts? Thanks for any help I little bit of myself. 36 yr old male, with a 15 old son, unfortunately living in Indiana. I've had fish/pets most of my live, and I currently have a 3 yr old female German Shepherd, a 40g long freshwater with a 10" Arowana, 4" Firemouth, and a 4" albino Oscar, with a couple 3"-4" algae eaters. 55g tank with a 16 yr old male painted turtle that was found on a golf course, and we think it was hit with a mower because he is missing a rear leg..