Hard water stains!

[Eclipse2010]

I've used an old 85 gallon tank to make my bearded dragons cage. I've got all the lighting and decorations just right, but there is still residual hard water stains on the sides of the glass which I can't get off no matter what I try. I have tried super fine wet sandpaper, vinegar and dawn soap with a magic eraser. Any ideas of something I can try? I can move her to a much smaller tank and use chemicals if I have to, but I'd like to avoid that if at all possible.

 

[CooperDragon]

You could try rubbing toothpaste on an area, let it sit for a bit and then rinse it with a vinegar/water mixture and see if that gets the stains out. Bar Keeper's Friend is known to be able to get hard water stains out too. I usually keep some of that in my kitchen and use it on pots/pans. It's an acid so you'll want to rinse it very well with water afterward but it's likely to do the trick.