390835 Size: 15 Pound Pictured in 15 Pound size Features: -Pond care. -Ingredients: 25pct Copper Compound in fine crystal form. -Used for control of algae growth in lakes and ponds. -Do not use in waters containing koi, hybrid goldfish, or trout (if hardness of the water is <50ppm). -Available in 5 pound and 15 pound sizes.