It's getting more common in normal freshwater petshops here, I bought a fat 15cm bottle from Harry's Aquamart at Changi Village. It is actually the extract of a tea tree (Melaleuca sp.) and smells like tea. No copper. I used it in a quarantine tank for 2 clowns last time, but it doesn't seem to hurt amphipods and copepods so it should be reef safe. I've heard of other people using it in their reefs with no problem, and it doesn't matter if you overdose a bit.
This is the description of Melafix, but the picture of it is slightly different than what I bought : http://www.rena.net/us/rena_melafix.html
The one with the correct picture is at http://www.mops.on.ca/products/MEAF-11H.htm .