I bought a tank from a guy who apparently never, ever, prolly didnt even think about cleaning the glass. There are water spots that just will not go away. I have tried windex, water, microfiber towels, perfect glass (another glass cleaner), all with no results. It is really bugging me because they only really show up when I am taking photos. So, does anyone have a suggestion? The tank is up and running with fish so nothing too caustic.