This sphere is preloaded with a natural bacteria and enzyme blend which reduces excess nutrients, sludge and ammonia, resulting in improved water quality and clarity. A patented timed-release system incubates and releases beneficial bacteria and enzymes 24 hours a day, 7 days a week, over a 30-day period. Each sphere treats up to 12,500 gallons (to calculate pond volume in gallons, multiply pond length x width x average depth x 7.5). Being all-natural, you can't overtreat. PRO formula works effectively in water from 34° to 110°F. Safe for humans, pets, fish and plants. Made from a corn-based polymer; after 30 days, sphere can be disposed of or composted. Replace sphere every 30 days. 2-pack treats up to 12,500 gallons for 60 days, or 12,500 to 25,000 gallons for 30 days. May require 4-6 weeks to achieve water quality improvement. Most effective in ponds with pH level between 6.0 and 8.5. Made in USA.