When I get this heavy thing down to the barn I think that I will give the vinegar a try. I'll have plenty of time to play with it as I'm definately putting the iggys into a 50 gal. It'll give me back about 6" of my bedroom.

__________________
Fran
January 9, 1940 - June 1, 2006 (R.I.P)

Fran buddy I hate to discourage you but I am not sure that the minerals do not sort of etch the glass. I have a 55 gal that I used to have fresh water in and the previous owner (also freshwater), had a tendency to let the water level drop. There is an area around the top of the tank which has that same discoloration you are referring too. When it was full of water it was not visible but when dry looks like ****! I have tried lemon juice, vinegar, salt,
commercial glass cleaners and nothing seems to touch it.

__________________
Merlin,
What's Life Without A Little Magic!

Thank you Marv. Hearing that from you of all my friends is going to save me bunches of experimentation. That is exactly what I have here. Houdini glass. I'll put this one down there and forget it exists unless someone wants it for fish.

__________________
Fran
January 9, 1940 - June 1, 2006 (R.I.P)