Blanketweed is the common name given to a group of string like filamentous algae that include the species Spirogyra, Cladophera and Ulothrix. This group of algae can become a major problem in garden ponds in the spring and summer months, as the water warms up this problem only increases. Without treatment your pond can become choked with these weeds, killing plants and fish alike.
Unfortunately for the pond keeper blanketweed has an affinity for clear well oxygenated water, the conditions most of us would like to see in our ponds. This is especially true for Koi ponds where the water is kept crystal clear with UV lights and extra oxygenation provided by Venturis. Garden ponds often have aggressive growths of blanket weed around waterfall inlets.
Because of the many varying factures, size, location, water quality, climate, live stock, etc, no two ponds are the same. Add to this the different species of string algae that could be growing in your pond there is no one treatment treats all cure. The best we can advise on the treatment of this troublesome problem is that if one product does not seem to work then try another, there are plenty of alternatives. Ask friends and neighbours with similar sized ponds in your area what has worked for them and give that a go. You should not expect instant results, most blanketweed treatments require that you use them for a few weeks as they work biologically and the bacteria’s and enzymes need time to do their job. With that in mind we have listed a selection of popular blanketweed treatments below.