After many investments in pond aids, all of which supposedly would be effective, advised me a friend on vacation this means apply. In so-called specialty stores, I found it not. So I rummaged in net and found one. I have used for a 20000ltr Päcken, 2FIlteranlagen run through the UV clarifier and are turned off. After two weeks the water was algae-free. Now 2 months in use, still no seaweed. Of course, many residues, but with regular cleaning of filters, accumulate dead water lilies parts, it just gets better. Top items. Can only be recommended.
