RP Ammonia Block Marine 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 800 litres of water. For use in reef and marine aquariums.