Calcium Buildup?

[mpatz]

Hey guys,
Im new to the forum but not the hobby.
I just recently bought a 65g tank and stand off Craigslist. Leak checked and all good. Was run for 3 months saltwater b4 I got it.
I went to clean the tank itself with 50/50 vinegar/water and noticed some white build up.
I CANNOT get this stuff off
Tried straight vinegar
Tried a razor blade
Even tried a dremel with a soft bristle round brush and that barely took any off.
Any ideas how to get it off?
Here are some pics (sry had to use flash)
Thanks

 

[mpatz]

Oh also ive noticed when its wet it pretty much disappears until it drys.
Do you think it would still be visable when the tank is full?

 

[DFW]

You might need a miracle. Does it feel like the glass has been etched? Does it feel different there than the clear areas?

 

[mpatz]

Feels very slightly rough but smooth and some spots are def built up on the glass. Most of those I was able to get with the razor blade.
Doesn't really feel like its etched into the glass (like a scratch), feels almost like a smooth layer on top. Im really hoping its not etched. This may be a stupid question but, is it possible to buff something like that out?

 

[mpatz]

http://www.bayoureefkeeping.com/topic/6180-how-to-remove-hard-water-staining-from-your-aquarium/
Found this link looks like it might work but I wonder if the cleaner the guy used would be toxic...

 

[DFW]

I was wondering if someone left a puddle of acid laying there.

 

[mpatz]

I might just get the front pane replaced with low iron glass. Theres a glass place near me that does aquarium repair, just hoping it doesnt cost a fortune.