Hard water stains

[blkhawk10]

so I have a hazy looking part of my rimless tank that I can't get off. I've tried vinegar, lemon, baking soda, bar keepers friend and a magic erase sponge...tomorrow I'm getting a pumice stone to see if that works. Does anyone know of anything that I possibly could do to get rid of the stain?

 

[Randy Holmes-Farley Verified Community Expert]

If it is a deposit as opposed to a roughening of the glass, muriatic acid diluted 1 part acid into 10 part freshwater will work a LOT faster than vinegar to dissolve it.

The cleaner CLR Calcium Lime and Rust Remover may also work.

 

[blkhawk10]

If I use CLR will I be able to put fish and corals back in the tank? I was under the impression to not use cleaners like that because I wouldn't be able to put fish back in the tank. How would I be able to tell if it was a roughening of the glass?