RP Ammonia Block eradicates poisonous ammonia infinitely quicker than other products on the market. It removes all ammonia and ammonium from aquariums within 4 hours. New aquariums can be fully stocked once set up without the fear of an ammonia spike or loosing fish. Each pack contains 3x 100g pods sufficient for up to 600 litres of water. Can be used in both freshwater and marine aquariums. RP Ammonia Block uses a unique premium-grade ammonia selective ion-exchange resin to quickly remove ammonia from aquarium water. This is a similar method to what is used in many other industries.