Treating Green Pond Water

Green pond water can indicate an overabundance of bacteria. This could mean that something is out of balance in your pond. You may have overstocked it, or perhaps it needs a partial water change. Your pond needs treatment similar to a fish tank if you plan to keep fish. This includes biological filtration which will keep the ammonia and nitrite that can become toxic to your fish. While some ponds may survive if you have adequate plants and small numbers of fish, it is recommended that you provide some sort of filtration to make up for the lack of filtration that nature offers in real ponds.

If you want to overload your pond and not provide adequate filtration you will soon see green pond water and dead fish. As your fish eat and expel waste, they create pollution in their own pond. As time goes on and more waste is expelled, the pond becomes more polluted and the fish eventually die. Bacterial filtration will produce "good" bacteria that eats the "bad" bacteria and keep the toxic levels in your pond in check. It is also a good idea to do a partial water change every month or so.

When filtration does not get rid of green pond water, it is advised that you use an ultraviolet sterilizer. These are installed in the plumbing outside the pond and work by killing algae, bacteria and parasites suspended in your pond water before the water is returned to the pond.