Bermuda Barley Straw is an effective alternative for controlling algae in ponds. The treatment is completely safe for fish, wildlife, pets, plants and humans. Simply place the barley pouch in your pond and the decomposing straw releases chemical compounds that help to control the algae population. Barley straw works best where there is some water movement, so ideally site near a waterfall, fountain or filter outlet as this is where the pond will generate the most oxygen allowing the barley straw to work. Bermuda barleystraw should be placed in the pond in early May before the pond water starts to warm and algae starts to take hold. Ensure that the pond is well oxygenated as levels of oxygen may be removed from the pond during the decomposition stage. Will treat 2250 litres/500 gallons for 6 months.