copper sulphate and lillies?

[perplexed ponder]

Anyone know how copper sulphate and lillies mix?
I donated some lillies to the township pond. They are putting up pads, but the buds aren't surfacing and look pretty bad. They keep dumping copper sulphate in the pond to kill string algae (instead of trying to fix the situation).
Is it harming the lillies (hardy)?

[miguynmkoi]

???  If it kills algae that means it will kill plants, including the lilies!!!  Very generous of you to donate your lilies but I think that pond either needs more filtration or more plants to cover the water surface.

This works in my pond.