Rock and Waterfall cleaner is a great for killing string algae in your pond. Rock and Waterfall cleaner can be used as the first line of defense to quickly and safely break down string algae from waterfalls, streams, rocks and other areas where algae is growing. Start using rock and waterfall cleaner to spot treat the trouble areas in the pond and follow up Pond Bacteria Dry with barley straw on a monthly basis to help keep it away. Rock and Waterfall cleaner works by oxidation to provide fast results! Simply turn off your waterfall and stream and sprinkle it directly onto the algae. Wait a few minutes and then turn your pond pump back on. You will see some results in minutes! The rest of the results will come in the days following the treatment as the algae dies. No harm to fish or the envirement. Breaks downs immediately once it hits the water. Rock and Waterfall cleaner works great in cold pond water! Starts working within minutes of application!!! Rock and Waterfall Cleaner 2.5 lbs. RW2B Rock and Waterfall Cleaner 8 lbs. RW8 Algae Control Combo Pack Great Value! ponddepot@msn.com Copyright - All World Rights Reserved Pond pumps, Pond Kits and Pondless Waterfall kits, Underwater Pond Lights. Aquaclearer Extreme bacteria and String Algae Buster and pond fish food. Pond Depot provides Do-it-yourself pond kits and Pondless waterfall kits delivered right to your home at great prices! Thank you for shopping at Pond Depot you online pond superstore!