from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A substance used to kill or inhibit the growth of algae.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A substance that kills, or inhibits the growth of, algae.
from The Century Dictionary and Cyclopedia
- n. Any substance, as copper sulphate, which has the property of destroying algæ.
And you can also add a little algicide to your fountain as well as a little chloro to help maintain good condition of the water.
Potassium permanganate (KMnO4) is used as a bactericide and algicide in water and wastewater treatment, and as an oxidant in organic chemical synthesis.
While copper does not generally pose risks to human health, it is extremely toxic to marine algae and invertebrates, and is even used as an algicide.