I got a 20 gallon tank from someone I know and it had a bunch of hard water stains in it. Looked like lime build up? I was able to scrap all of it off and I let the tank sit in pure vinegar for two days. All of the stuff came off and was sitting at the bottom. Now the glass is really smooth but has a milky look to it. I've taken vinegar and rubbed the tank down in it and that didnt work at all..

What else can I try to get the glass more clear?