Tank glass ruined

[Anna Piranha]

I have a 37g aquarium that I use for emergencies (like the time I didn't tighten the valves on my cannister filter :o )
The tank is several years old. After each use I clean it with a bleach solution, which I rinse thoroughly over and over again. Then it goes in the basement where it waits for the next emergency. I looked at it yesterday and found that the glass is milky white over most of it. The problem seems to be within the glass itself. I scrubbed with a commercial aquarium cleaning product, to no avail. I then tried the bleach solution. It didn’t work. I scrubbed and scrubbed, but the problem remained. A small area on the tank is not affected, so that I realized a difference in texture between the affected glass and the clear. It has an ever-so-slight roughness about it. I cannot for the life of me figure out how this happened. More importantly, I don’t know if it is safe to house fish. Does anyone have any experience with such a thing?

[ChloroPhil]

It's probably scuffed up from some sort of scrubbing. I'd use it to make a Wet/Dry filter or a plant grow-out tank.

[RAWesolowski]

Anna,

Was it near your furnace or hot water heater? Glass exposed to the chemicals in natural gas will get a milky haze over time. I have not found anything that will restore it.

[Anna Piranha]

Thanks for all replies to my message. Though the tank has never been stored near a heat source or any of those mentioned, I have learned some things from your replies. I will be mindful of where I store tanks in the future. Thanks again...Anna

[fossil]

hey I have no idea if this is it but it might help-

I used to have really old kitchen glasses that were about 3 or 4 years old. After being washed over and over again the glass turned a frosty white. Maybe your tank went through the same kind of thing. It was washed so much it may have turned a white. I think it would be find to put fish in there buy a few cheap tetras and find out.