Seapora Snail Zap eliminates nuisance snails in freshwater aquariums. Remove any activated carbon from your filter, add 1 drop of Snail Zap for every gallon of aquarium water. When the snails drop to the bottom (or after a period of three days), do a thorough gravel cleaning and 10-25% water change. Replace the activated carbon filter upon completion of treatment. Repeat as necessary. Will not harm fish, plants, or biological filter.