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Causes of Water Quality Problems in Ponds

Causes of Water Quality Problems in Ponds

Decorative water features and fish ponds can be a lot of fun to create and maintain. They enhance the aesthetics of the property and can even yield schools of fish to admire or (depending on the variety) even eat.

However, water quality can be difficult to maintain. If you are new to the joys of cultivating a water feature and would like to know how to keep your water quality under control, then read on. We’re going to look at a few of the likeliest culprits for poor water quality in decorative water features and fish ponds.

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Image Credit –

ü Inappropriate temperature

Inappropriate water temperature is one of the likeliest causes of problems with ponds that are stocked with fish. Shallow ponds are going to become much warmer in the sunlight, while shallow ponds and those fed by underground springs are going to be cooler. There is little you can do to modulate the temperature of a pond, so it’s best to determine the temperature of your pond and stock it accordingly.

Generally speaking, bluegill and bass like warmer temperatures (mid-20°C range), while cold-water fish such as trout prefer it a bit cooler (low 20°C range). You may be able to cool a pond in summer by feeding it with groundwater, but this is honestly an uphill battle. Stock your fish pond accordingly.

ü Oxygen-poor water

Oxygen-poor water is a poor habitat for fish. This is most likely to occur when aquatic plants grow and then die en masse. The bacteria that break them down use up the remaining oxygen. This can be controlled by using an aquatic herbicide to subdue algae growth to begin with.

ü Poor nutrient balance

Obviously, you want your pond to have plenty of healthy nutrients in it to sustain the fish and aquatic plant life living in it. However, imbalanced nutrients can lead to the growth of organisms that you would rather not have in your pond – such as unhealthy bacteria and algae. Phosphorous, in particular, readily cultivates the growth of algae.

While you may be using a special nutrient mix on your pond to maintain balance, keep an eye on other sources of nutrient imbalance that could throw off your pond’s equilibrium. These include:

  • Vegetation and silt at the bottom of the lake
  • Excessive run-off from the surrounding area
  • An incoming water source such as a drainage ditch, spring or stream

None of the above are necessarily bad in their own right. However, if you begin to notice foul odours, dead fish or excessive algae, look for inlets that may be introducing unwanted nutrients into your pond ecosystem.

ü Muddy water

Muddy water probably won’t harm the ecosystem of your pond, but it can certainly be an eyesore. The greatest single cause of muddy water is run-off from areas around the pond. Bottom-feeding fish can also be the culprit. To eliminate this problem, plant vegetation around the pond to prevent runoff; consider culling your bottom feeders; and root out pests such as muskrats or beavers. Ground limestone can help to keep sediment down, while blooms of zooplankton (which only occur in warm summer weather) can be subdued with copper sulphate – though the latter is going to harm the pond’s ecosystem.


A watchful eye and a commitment to preventative maintenance are the two most important factors in maintaining a well-balanced pond. Beyond that, it’s a good idea to know which local experts you can turn to should the problem escalate out of your control.

Author’s bio:

Jacob Gilbert is a long-time koi fish enthusiast who has since branched out into maintaining larger aquatic ecosystems and helping others to do the same. He has several years of experience working with water feature installation specialists such as Water Garden, and he shares this know-how with other enthusiasts via blogging.

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