Cracked tank?

[Myka]

Originally Posted by sharuq1

was getting all the Ca to precipitate on the off chance there is any Cu bound up in it

I agree, if it's a crack you need to replace the pane of glass or replace the tank. Often it's cheaper and easier to just replace the tank.

If the tank was treated with copper, then your biggest worry would be the silicone. The silicone will absorb copper, and there is nothing you can do to get it out. If the silicone has a slight green/teal tinge to it, then it most definately has had copper in it. If the silicone is still clear, that is still not a sure way to say it wasn't treated.