GreenClean Pro - GranularGreenClean Pro is sold in a 50 lb. bag. GreenClean Pro is a professional strength granular algaecide that eliminates a broad spectrum of algae contact. Through the process of oxidation, it breaks down the enzymes and protein that make up a simple cell organism such as algae. It attacks the cell wall and destroys the internal structure of the simple cell. Dosage Rate: Rates vary from 8 25 pounds per acre ft of water. See label for application rate.