Nava Chemicals 652222022 Algaecide 50, 1-Quart Bottle Water treatment effective against all types of algae Effective against chlorella pyrenoidosa (green algae), phornidium inundatum (blue-green algae) Also effective against phormidium retzii (blue-green algae) and lyngbya versicolor (blue-green algae) Quaternary ammonium compound, a clear, colorless to straw colored liquid