This decorative refillable floating dispenser uses 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. Treats up to 2,500 gallons (to calculate pond volume in gallons, multiply 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. After 30 days, simply replace the refill packet. May require 4-6 weeks to achieve water quality improvement. Most effective in ponds with pH level between 6.0 and 8.5. Includes 2 packets for 60 days of treatment. Additional packets are sold separately. Made in USA.