Poolife Algaecide 90Poolife Algaecide 90: a powerful, long lasting 90% polyquat algaecide designed to prevent and eliminate stubborn green, black, and yellow mustard algae. This non foaming, non staining formula is ideal for weekly maintenance and safe for use in all pool types, including those with attached spas and water features. Keeps water crystal clear and algae free without affecting pH levels.