We are constantly being asked by pond owners for advice about how to deal with the problem of algae carpets on the water surface. These green, almost foamy carpets either float like little algae islands on the water surface or gather around the edge of the pond like green lace.
These are green algae and they need to be treated the same way as the more familiar thread algae. Phosphate deposits allow them to grow and then they trap air to float on the water surface (article tip: Algae in Sight: Pollen and Blossoms as Growth Engines ).
Because these algae are easier to reach than many other types of algae, the starting point is ideal. Instead of treating the algae with an anti-algae agent (which would mean releasing the bound nutrients into the water) the layers can be mechanically removed with a catch net or a sludge suction cleaner. This way not only the algae but also the absorbed nutrients in them will disappear from your pond.
Should there be thread algae or other patches of green algae in the deeper water zones, you can sprinkle this area directly with JBL AlgoPond direct . The algae will decompose within a few minutes. Stubborn areas need to be treated again at intervals of 48 hours. You can net a part of the dead algae off the water surface. Firmly anchored algae will die off under water. They won’t float upwards, but will become greyish and become broken down by bacteria.
Don’t forget to bind the released nutrients afterwards with JBL PhosEX Pond Direct (please take the carbonate hardness into account) to avoid to shifting the problem and ending up with floating algae.