Aquarium Systems Test Kit A new range of test kits from Aquarium Systems that accurately test your pond/aquarium water. The Seatest Ammonia test contains approximately 40 tests for the presence of NH4, or ammonium compounds, in your marine or tropical aquarium. Ammonia and ammonium is generated through the breakdown of fish food and fish waste, and is usually converted efficiently to nitrites and then nitrates by the nitrifying bacteria in your aquarium and filter. However, a new tank that has not been cycled, or a new,sterile filter, can cause a build up of ammonium compounds which will adversely affect fish health. Please note this product is short dated - BBE August 2015.