Super Size!

Before planning anything out, I would fill it again, let it run with a circulation pump for a day, then test for copper. If it was used as a fresh water tank, it more than likely would have had copper in it, in which case it couldn't be used for a reef tank.

 

Does copper permeate the silicone or something...? My 60 gal was a used Oceanic, and I was given similar advice in regard to copper there as well.

 

Yes. The silicone will then leach copper back into the water at toxic levels, I think some have found for up to 10-15 years after wards.
It would just be best to check and make sure rather than finding out about when you try to add corals or inverts.

 

YEa, you do not want to try and drill tempered glass, it will shatter the glass.......