i agree with tmoving the rocks around as much as possible without changing/disrupting your whole setup. also, try to mess with the tangs hangout as much as you can. if you can move around the rocks by your tangs "favorite spot" and move around a few powerheads to change your flow, the tang will become confused and hav to find a new home. so the tang will restablish itself as the same time as the copperband.
althoguuh this isnt some muricle that can tpossibly fail, it certainly beats nothing.
adn, if possible, throw the tang in the sump, do all this, let the CBB settle in, then put tang back in
good luck and let us know what you choose to do!