Healthy Ponds 52210 All Purpose Water Cleaner 100 - Reloadable Dispenser with 2 30-Day Refills; Treats up to 100 Gallons for 60 Days Keeps aquariums, fountains, rain barrels and water features from 10-100 gallons clean, clear and free of green organic growth Unique patented time-release system delivers a proprietary blend of naturally occurring bacteria and enzymes into the water for 30 days Veterinarian approved and safe for fish, plants, birds, animals and humans Results may vary; over time bacteria and enzymes will work to reduce organic debris, improving water quality and clarity while eliminating odor Includes reloadable dispenser with 2 30-day refills; treats up to 100 gallons for 60 days