Hydrothol-191 Liquid is an excellent alternative to copper products...
Hydrothol is a registered, broad spectrum, organic, aquatic algaecide and herbicide. It is an excellent alternative to copper products. Hydrothol is effective on controlling hydrilla, milfoil, pond-weeds, elodea, chara, spirogyra, and pithophora. This product can be harmful to fish populations if used incorrectly. When using, always wear gloves, eye protection, and cover skin.