Koi Ponds: Green, Murky Ponds & Algae

Page Summary:  Nobody can enjoy a cloudy green or murky brown koi or goldfish pond. Yet so many people tolerate this situation. They empty the pond and the water is clear for a day and then it goes murky again. So they empty the pond again and so it goes on. Murkiness in a pond cannot be overcome by pumping out water and refilling it alone. Sure it might work for a while but the green or brown murkiness will re-appear. This reason is that there are green or brown algae particles suspended in the water close to the surface where they gather to collect sunlight to allow themselves to grow and recreate. Special UV (ultra Violet Light) equipment is required to control murkiness in a koi or goldfish pond


Yours: A crystal clear koi pond

If you keep koi and you really want to enjoy your koi collection, you will want the pond water to be as crystal clear as possible. To achieve this, all you need do is avoid all the causes of murky water. These are some of the most common causes.

Excessive algae growth

Algae bloom is one of the most common causes of cloudy, green or murky water. It is most problematic in summer, when the weather is warm.

To minimise the growth of algae, you can plant around the pond to shade it, and also plant inside the pond.

Water lilies are great for providing surface shade from within the pond, while oxygenators that float in the body of water successfully compete against algae for space in the pond.

At the same time, these valuable plants absorb the dissolved mineral salts and carbon dioxide that the algae thrive on, thus helping to keep the water crystal clear.

Another solution is to install a UVC (a UV clarifier) that literally kills the algae. Relying on UV radiation to do the job, a UVC is fitted between the pump and the filter.

Its active mechanism is a UV light bulb which simply needs to be replaced once a year.

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Overfeeding your koi

Of course it isnt the fact that you are feeding your fish too much, but rather what happens to the food they dont eat that makes the difference here. Excess food will degenerate and if it contains food dyes, these will leach into the water. Both will affect the appearance and quality of the water.

The biological filter hasnt matured

While a bio filter is preferred by most koi keepers, it does take time for the biological action of the filter to mature fully, while the necessary bacteria in the filter establish themselves. If the filter hasnt matured, you are likely to get high nitrite readings, and the water will inevitably be milky in appearance. So until the filter matures, youre going to need to take steps to get rid of the nitrates that make an unwelcome appearance.

The pond isnt balanced

It isnt just the pond water that needs to be balanced. The pond itself must be balanced. A balanced pool will contain plants and a range of creatures, from larvae to fish and visiting amphibians. You will see dragonflies and smaller damselflies, and birds in search of insects or even fish.

A balanced pond develops a natural food chain. For instance, some birds, including swallows, are attracted by insects in the pond water. Certain plants, including some of the rush species, attract insects. Plants around the pond, that produce seeds and berries, will also attract birds. Then there are numerous microscopic plants in the water that contribute to the natural balance of the pond and its food chain. Even algae which we normally consider a pest, is part of the food chain. Not only is it nibbled by the very fish we stock the pond with, but it also plays a vital role providing food for smaller pond life.

Plants play a very important role in sustaining the life of all the organisms and creatures that live in the pond habitat. However different types of plants each play a different part, some providing shade, other providing food, still others creating ideal hideaways for fry or a place for adult females to spawn.

The fish themselves also play an important role, helping to balance the ecosystem by eating insects and smaller creatures.

While you will introduce the koi to the pond, if you maintain your koi pond sensitively, you can simply leave the rest to nature.

Dont stress over pond pH and Testing Koi Pond pH

Interpet Koi Pond Test Kit

I will make a few very important points here which should be taken very seriously by anyone contemplating measuring pH in a koi pond and then TAKING ACTION based upon the measured result from testing the koi ponds water. If you test do it reliably... Interpet lead this pond water testing field of the koi keeping hobby

  1. pH of koi pond water will vary depending on time of day measurement is taken and especially if plants are in the pond. This means if you take a pH at 9am it will not be the same as a pH taken at 6pm. This single piece of information therefore must never be the information relied upon to make fundamental decisions
  2. pH is notoriously difficult to measure even in a laboratory with sophisticated instruments let alone in a koipond or fish pond using a piece of litmus type paper or a vial with coloured scales on it.
  3. If you must measure pond pH and this is a great part of the hobby then take the pond pH at the same time every day and plot the result on a graph. So now what youre looking for is not a single pondwater result but rather a pH trend in the pond water that you can use to sensibly consider a pH strategy.
  4. Very high pH in a koi pond is a serious threat to the well being of koi when levels reach about 9.5 because at this pH level ammonia which is a natural metabolic product of the koi and its existence becomes extremely poisonous
  5. It would be extremely rare for a koi pond to reach dangerous pH levels but could well occur in koi ponds with serious algae problems

Articles about koi and fish pond care in winter

Pond Heaters. Heating koi ponds winter growth feeding benefits

Koi pond heating using gas electric in UK temperature control

Bringing fish and pond and water out of winter into spring

Koi goldfish pond covers over winter. How to look after pondfish

Over-wintering koi goldfish hibernation cold freezing water ice

Koi pond heating using gas electric in UK temperature control

Should I heat my new koi pond this winter. What temperature?

Temperature swings. Koi Goldfish Feeding & water temperature

To Feed or not to feed your pond fish or koi or goldfish

How Do I care For My Garden Fish Pond In Cold Winter

Frozen Koi Ponds & Fish Ponds. Ponds Freeze in Winter. Pond Care in Freezing Winter Weather

Interpet Koi Pond Test KitWhat the Does pH of Koi Pond Water Mean? Should I measure Pond pH