Barley Straw Pond Logs – Barley straw is 100% natural and controls all types of algae blanketweed and blue green algae. Safe for fish, plants and all other pond life. A single log will treat up to 3,000 litres of pond water. The barley straw is packed loosely in net bags to allow the water to flow through it. The logs should ideally be placed in areas with good circulation tethered just below the surface. Pack of 3