I used CopperSafe in my 125g when it was still a FW tank. I added more sand to make a DSB, but other than raising the sg and adding LR, all I did was treat the water I was changing when I raised the sg and subsequent water changes with Amquel+. I now have a beatiful reef with tons of inverts, including lots of snails. The Amquel bottle state that it removes copper and I believe it. I have no issues keeping inverts and coral of any kind. Matter of fact, I even mixed the previous 1" layer of sand up with new live sand and some sand I bought from the local lumber store, so I am sure it is not buried under the new sand. Having said that, I would in no way treat a DT with copper, if I had a choice.