Filamentous is a common algae species that forms large green mats, islands, and shorline rings. Even the largest masses are composed of single cells grouped into filaments.
Color and appearance vary from cotton-like dark shades of green to bubbly bright green. It carpets the bottom of the water body and rises to the surface by trapping gasses. This rapid ascent from the bottom is how water goes from clean to infested overnight.
Where water, nutrients, and light are present algae will grow – it is not preventable. There are over 30,000 species of algae, each adapted to fill a niche. A consistent treatment program and quick response to growth are key to good control.