Blagdon 500ml Ammonia Remover Pond TreatmentAmmonia Remover will reduce levels of ammonia to a healthy level for fish and plants. This product should be used when: Ammonia test kits indicate the presence of toxic Ammonia Fish are sick or dying which is often caused by Ammonia poisoning. Biological filters are new (less than 6 weeks old) or have been damaged by treatments or interruption of water supply Lethal Chloramine is present in tap water. Key features: Harmless to filters and all species