Now I have no idea on the history of the tank ( copper or not ) the last owner had it set up as a reef. This tank will be my refuguim and I have pulled all of the silicon out and will reseal it - so my question is it the silicon that would hang on to the copper ( if there was any ) - Do you think I would be ok?

After you clean it and replace the silicon, you could do a copper test to be sure.

Nancy

I am assuming it should read 0 copper and will most stores run these test?

yes on both accounts... a copper test kits isnt more than a few dollars/pounds/euros to buy :)

any idea how long I should let it set with water in it (so that I can get a reading of read copper or not)? I mean should it have water in for a month before testing it?
Thanks,
John