JBL Algopond Direct Blanket Weed Remover 250g Problem-free application: simply scatter over the algae bed. The oxygen attacks the algae cells and destroys them. Effect is immediate, algae perish within hours. 30 – 50 g JBL AlgoPond Direct per 1000 l pond water. 30 g dosage for 800 l, 50 g dosage for 1000 l.