In the interest of full disclosure (and so the sales shills hawking copper products can't whine), please note that:

1. if alkalinity is not too high, and no chelants are present (Metal Magnet, HEDP, etc) are present copper levels above 0.5 ppm *can* kill many forms of algae.

2. 0.5 ppm copper will kill some types of bacteria . . . eventually. Not fast enough to be useful in a pool, but eventually.