Works quickly through the power of oxidation, breaking down algae cells on contact. Its organic chemistry immediately begins fighting algae blooms, releasing vital oxygen into the water as it biodegrades. Safe to use in any water feature containing fish, plants and aquatic life, you can feel good about using GreenClean. Eliminates string algae in ponds and on waterfalls. Visible results within minutes. Also use all season long as a preventative treatment. Chlorine, copper, and phosphate free.