Minerals should not have any affect on any type of invert, fish, or animal. Only nitrogen can have an adverse effect, and once the tank is cycled properly, that is not much of a concern.
The amount of copper in Flourish is so miniscule, it should have no effect at all on even the most sensitive invertebrates. 0.00001% is a ridiculously small amount. In fact, your tap water probably contains more. http://y.petalphile.com/cu