The Bermuda Barley Straw Mini Bale will help prevent the growth of algae and blanketweed in small ponds. Simply add the straw bale to your pond. Once the straw starts to decompose it will begin to release an enzyme which will help prevent the growth of algae. You will need to allow up to 4 weeks for the enzyme to be released. Treats up to 4,500 litres / 1,000 gallons for up to 6 months.