Does copper keep the algae down

[flyfishdoc]

There is a recent thread in the beginner forum about keeping algae down in the humidity (drip) tray. Some one mentioned putting copper wire or a penny in the tray to keep down the algae.

Would this work in the individual pots, i.e., to place a penny in the bottom of the s/h pot to keep the algae down? Would the copper harm the plant?

I know that the algae is not harmful, but since I keep my plants in the house, it the aesthetics I am thinking about.