yeah i know about meds and stuff but this is supposedly designed for reefs - i mean all inverts have some degree of sensitivity to Cu perhaps there is a beneficial form? such as with chaelated and non-cheleated iron? they couldnt be so stupid as to put coral poison in a reef additive...or could they?
Copper is a trace element and like all trace elements is essential for the well being of a reef. If you check the ingredients of some salt for aquarium use, you will see copper listed there too (as well as Arsenic and others!)
Our test kits are useless at detecting copper at these levels, so as long as out kits dont detect it in the water it is at a low enough level to not be a problem.
Octopuses blood is blue because it is copper based...
i cant remember which i think it is a seachem reef complete or something - i thought that might be the case... but then if it is ok in tiny amounts - how bad can the copper absorbed into the silicon be???