Barley Straw is a natural alternative to herbicides and chemicals for the prevention of filamentous algae. It will not kill existing algae but will prevent new growth from forming. Barley Straw will not harm fish or plants. In most cases, it actually increases the invertebrate population, providing additional food sources for fish. 

Sold in 8-ounce bales; each bale treats up to 1,000 gallons.