Pond Water Turning Green

Pond water turning green is a common problem associated with both natural and manmade ponds. The problem not only affects the appearance of your pond but also the quality of the water in it. The pond water turning green is also a recurrent one in nature. So you need to be very careful about how we can minimize the risk. In this article let us see how the ponds turn green, the underlying causes and how we can prevent this from happening in the best possible manner.

Green pond water

Pond water turns green because of the growth of tiny floating algae. They can grow at an explosive rate. This algal bloom results in pond water turning green. This is also known as pond scum

The green water algae are microscopic organisms having a single cell structure. These algae thrive well in warm water having higher nutrient levels. Hence the problem is more common in summer months when there is abundance of sunlight and the water is warm. The condition can be more aggrieved if the pond is new, where there are no algal predators being formed. New ponds may not have many flourishing plants which can compete with the algae for nutrients or even provide them with shade accelerating the growth of these.

Causes of algal bloom and resulting change in color of pond water

Controlling the algal growth in your pond can be the hardest maintenance problem faced by you. It is normal to have certain algal invasion in case of a newly set up pond, where, the algae flourishes till an ecological balance is reached. Good water circulation and pond life can act as favorable factors to achieve this balance.

Little algae in your pond should not be a matter of concern. However, if the algal growth is extreme, then this is something to be addressed quickly. Pond with algal bloom is unsightly and can have negative effects on the pond life. There can be a chain of negative effects to this phenomenon. All this can add to the maintenance cost.

The algal population of the pond depends largely on the weather of the location, the water temperature, the amount of sunlight received by the pond, the dissolved oxygen concentration in the water, the nutrient levels, and the plant life in the water and so on. So it is a cumulative effect of many factors which lead to hike in the algal population which in turn can make the pond water turn green. 

Spring and summer seasons can have more favorable conditions for algal bloom. During summer, the pond water will be warm for longer periods. And warm water can accelerate the growth of algae. Lack of proper proportion of plant species in the pond can also trigger algal growth. With less plant life, there is less shade and the algae will receive more sunlight which can cause them to multiply in numbers at a faster rate. Stagnation in the growth of already existing oxygen producing plants in the pond water can also favor algal growth. The sunlight can also increase the water temperature and thereby favor algal growth. The situation is aggravated during spring. During spring, the plant life would be trying to recover from the hard hit winter phase. So this situation can fuel the growth of these microscopic organisms.

Excess nutrients in the water can also favor algal growth. Run off during rains can lead to garden fertilizers and other chemicals entering into the pond. If you over fertilize your water plants, this too can increase the nutrient levels in the pond water. Too many fish species in the pond can also lead to excess nutrient release into the pond in the form of excrement. So what is important is proper proportion and balance. High pH value and low CH value can also have adverse effects leading to algal bloom and thereby turning the pond water green.

How can we prevent pond water from turning green?

Now as we have seen the possible causes of pond water turning green, let us see how we can prevent the situation. There are a number of measures with which we can fight the situation. The key is to prevent the explosive growth of algae.

Add Sufficient Plants

Good amount of aquatic plants can reduce algal growth. Be it floating plants or submerged plants a good amount of both is needed. Floating plants like lotus and lilies add shade thereby reducing the amount of sunlight reaching the pond which can control algal growth, while submerged plants like hornwort and anacharis can maintain proper oxygen levels in the pond water so as to help the useful bacteria to break down the single celled algae present in the water. The aquatic plants can also absorb the nitrates in the excrement of fish. This makes sure that the algae do not feed on the nitrates released in the water.

Adding sufficient quantity of fish

You need to add the right quantity of fish to the pond. There should be a balance in the plant and fish life in the pond. Keep the right quantity of fish based on the quantity of water in the pond. If you add more fish, then there excrements can add large quantities of nitrates into the pond water which can lead to algal bloom.

Never Overfeed fish

Even f you have the right quantity of fish, over feeding them can lead to the presence of more waste in the pond water be it in the form of excrements or the wasted food. This can also favor the growth of algal which thrive on them. So if you see leftovers, then adjust the feed you provide accordingly.

Using Aquatic Herbicides

Aquatic Herbicides like Pond Klear contains a wide range of useful bacteria which can target the algae and nutrients present in the pond. It can be considered as a beneficial bacteria treatment. They not only act on the algae but also on the fish waste and other organic matter, the presence of which can favor algal growth.

Adding Aeration devices

Aeration devices increase the amount of Oxygen in the water. This helps the useful bacteria in breaking down the algae. Pumps, filters, fountain, etc. can add in more Oxygen.

So pond water turning green is caused by algal bloom. It can be prevented by keeping a check on the algal growth. The above mentioned procedures can help in keeping the pond away from the explosive growth of the algae.