Using Zeolite in an environment such as an aquarium or pond is a great way of removing ammonia from the water, ammonia is highly toxic to fish.
What it does
Zeolite formulated for freshwater aquarium use will readily absorb ammonia, making it a useful media when dealing with ammonia spikes or potential spikes. It is important to know that zeolite does not remove every undesirable toxin in your tank, nor does it work forever. In fact, it becomes saturated fairly quickly, at which point it no longer provides any benefit. Generally within a month or less it is exhausted and should be replaced or recharged. In cases of extremely high ammonia levels, the zeolite may become exhausted in two weeks or less. When ammonia levels are elevated, always test frequently, replacing the zeolite as needed to until the desired results are achieved. Once the ammonia has been eliminated, remove the zeolite.
1g of zeolite removes approx 1.5mg of ammonia