The Underestimated Danger of Pond Nitrates


There’s a lot of information online about nitrates and their effect on pond chemistry and fish. We feel the information currently available gives a general underestimation of the potential danger excessive amounts of nitrates can cause. Not only for aquatic life such as fish, but also the health and quality of the pond water overall. If you really want your pond to thrive and have the ideal water parameters, read on to discover why your nitrate levels should be kept to an absolute minimum…

The Nitrogen Cycle Simplified 

Before diving into the dangers, let’s get a better understanding of what nitrates are and how they develop in ponds. Nitrates are the final by-product of the nitrogen cycle when the natural biology of a pond fails to discard of it. The nitrogen cycle is the process of when good bacteria, that go by the name of nitrosomonas break down ammonia, (in an effort to remove it) through the process of oxidisation and create nitrites. These nitrites would then further oxidise and be broken down by nitrobacter bacteria to create nitrates, a compound composed of one part nitrogen to three parts oxygen.

What Causes Nitrates in Ponds?

Nitrogen is often introduced into a pond system by fish some way or another. Fish therefore tend to be the biggest cause of high nitrate levels. However for many, getting rid of the fish in your pond is out the question (we don’t blame you). The most common causes of high nitrates in ponds in relation to fish would be the over-feeding of fish or excessive amounts of fish. Both of these factors contribute to the production of ammonia levels through waste produce (through dead food or fish waste) which triggers the process of the nitrogen cycle that eventually leads to the presence of nitrates.

What are the Signs and Symptoms of High Pond Nitrate Levels?

Because fish tend to be the primary reason for the presence of nitrates in ponds, it only makes sense that they are a great indication as to whether a pond is clear of or infested by them. Consequences can be very severe for fish if nitrate levels are excessive.

The straightforward signs can be observed in fish behaviour within a pond. If fish tend to swim at the pond surface gasping or if they often appear lethargic despite being well fed, then this may well indicate the presence of nitrates. Although, this is not to say don’t rule out other potential causes, pond nitrates are often something overlooked when such behaviour can’t be explained. Another common sign may be redness on the fish body such as redness in the fins or other areas.

More severe signals are when your fish develop disease or illness. As a result of high pond nitrates, fish are susceptible to a condition known as ‘brown-blood disease’. This happens when a fish’ blood stream is contaminated with nitrates which enter from the water into their blood through their gills (turning the fish blood into a dark brown colour). This prevents red blood cells from efficiently absorbing oxygen from the water and in turn explains why fish may be gasping for air at the surface of the pond despite there being adequate oxygen levels throughout the pond water.

Flip-over disease is another condition that fish, in particular goldfish may develop. This is when a fish loses its ability to say up right in water, in a lot cases the fish may end up floating helplessly at the surface of the water. This condition can be caused by a variety of this but high pond nitrate levels is a notable culprit when this occurs.

How to Manage Pond Nitrates Levels

Fortunately, nitrate levels are something that can be kept under control with a little care and caution. We advise that if you are suffering from high pond nitrate levels, that you introduce more beneficial bacteria into your pond through the use of Nitrate Klear, which is able to break down and remove the excess nitrates.

Ideally your pond nitrate levels should as close to of 0.00 ppm (parts per million)as possible, any reading within the range of 0.25 ppm or more is dangerous and you should take action to reduce the levels.

Other things to consider would be whether you are over-feeding fish or if you have too many fish. Nitrate levels will become easier to manage overall if you keep a balance in the natural biology of your pond.


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