Quick Links

Monday, May 6, 2013

Combating Algae

May has been a very hot month this year with the mercury crossing 42-43 degree Celsius. I do not think last 2 years have been as hot. We should be getting a couple of showers this week which should cool down things considerably. Last couple of monsoons have been deficient and we are hoping this year we get ample rains.

We have noticed that in the last couple of months, algae growth in our irrigation tanks has increased tremendously. We have emptied the tank totally dry, scraped the walls and floors and refilled it. However, a couple of days later, the green matter re-emerged.

I believe it is due to the extreme heat, however the challenge is to contain it to an acceptable level. Our current school of fish (katla and 'tiger shark') in the tank have not been very effective in combating the problem.

Below is a pic of our staff 'fishing' out algae. They love to get into the tank this given that they get a chance to cool off in the simmering heat.

Has anybody expressed this issue? If so, we would be happy to hear some suggestions how to control the issue. 


  1. Just a thought from another techie :)
    Algae need two things nutrient and sunlight. It may be difficult to remove the nutrients from the water, but you can try covering the tanks with black polythene. Not sure about the size of your tanks but just a thought ....


  2. Thanks for your comments.
    Size of tank is 40x40 ft and securing it effectively is a challenge. It is work in progress, will update when we have something in place.

    1. Hi You can try adding around 225 gms of Copper sulphate pre dissolved in around 4-5 litres of water to your pond of 40ftX40ft. (I suppose the height of the pond to be aound 3 ft). CuSO4 is recommended for controlling algae in water streams and ponds. The actual dosage is about 2 kg per acre feet of water. (So cross check if the above dosage of 225 gms for your pond is correct.
      All d best
      BN Ravindra.

  3. Previously, you have gone for Tiger Fish, if I remember correctly. Instead, my suggestion would be to go for Silver Carp, Katla as these are top level feeders in the tank/pond etc.
    Alternatively, you can also go for Tilapia but these are heavy breeders and small in size and hence you need to catch and sell them off at regular intervals.

  4. Last time, we had Katla as well but eventually not many survived. I will try Silver Carp and Tilapia..Thanks for the suggestion.

    1. What size of fingerlings did you use last time? The size should be minimum of 3-4 inches.

    2. Yes, they were about that size at the time of purchase..

  5. In our area we used to cover it with shade net (70% coverage or more). You can see this net used in plant nurseries.

    1. Anand,
      I have thought about using shadenet. However, how do you ensure it stays put and not get dislodged during heavy winds..?

  6. Hi Please provide some info about buying agri land near by savera farm in sivaganga dist.
    How much per acre
    And also provide some info about the ground water level in your area.

  7. hello techie, I'm Chezhian from Madurai. my native place is nearby sivagangai (okkur). ok, why can't you grow "azola". It'll solve your algae problems absolutely. thanks for your interest in activities of agriculture. bye.

    1. Hi Muthu,
      Could you please clarify more on this ? Do you mean growing azola in tank ? If so, would it block the drippers when I use the drip system ?

  8. dry the tank completely clean it ,dry it for 1-2 days

    Apply Limestone (Sunaambu in tamil ) paint at walls side ...

    1. Thanks for the suggestion. Would it not react with water when we refill the tank, thereby changing the pH ?

  9. The best thing to do is to cover the tank, thereby blocking sunlight. Painting with limestone will not last long and is a temporary solution.

  10. put few mango leaves ,,remove it after 8 hours..

    Ideally the reason for fast growth of algae is non cleaning process on side walls ..most of time only top portion only removed..These days much advanced technology have come.

    After applying limestone/latest non dissolvable type ,dry it to maximum so the wet portion is isolated.

    Cleaning of tank is regular process biweekly release all water let the tank dry in whole sunlight..

    It wont cost much ..60rs 5kg bag .

  11. Hi Techie2aggie,

    I have been fish hobby for many years, up to my knowledge, every organism need food to grow. for Green algae to appear, it needs lot of nutrients + lot of sunlight to grow. Basically nutrients appear in because of fish waste. There is something nitrogen cycle (aquatic). Please have a read.

    In ur pond, it has both the conditions thats is why you see it. You have to cut off either one of this. cutting off sunligh would result in less reproductive in fish.

    To cut off the nutrients reduce the no of fishes in the pond or do some planting in ponds. if you need some ideas in how to do planting in the ponds. we have goodle. i am happy to help if you need my hand. Thanks - Techie

    1. Thanks for your comments. I would be interested in knowing what can be planted in the tank.

    2. Here are the few information about algae and how to fight it naturally. I hope I dont waste ur time with a big post. Anyhow you can have a read. BTW knowledge is not harm :) :):)


      Natural Algae Treatment

      There are several things you can do to lessen or eliminate a mild or moderate algae bloom with out the use of chemicals.

      1. Manual rake or pull out all you can reach. Use a soft brush if necessary. Your pump should be able to pump at least 1/2 of the total volume of your pond every hour.

      2. Plant coverage should be 50% - 70% of the surface. Add a variety to compete with algae for the nutrients. Water lilies will shade the surface of the pond. Submerged plants (Anacharis) and floating plants (Water Lettuce, Water Hyacinth) absorb nutrients directly from the water with their roots.

      3. Add 1 Barley Straw Bundle per 1000 gallons of water. Keep submerged but do not let them sink to the bottom of the pond. They need light and oxygen to break down.

      4. Have the proper size biological filter for your size pond. Keep filter clean.

      5. Vacuum or siphon the bottom of the pond regularly.

      6. Add nitrifying bacteria (Microbe-Lift or Bio-Pond Tabs) which will help to starve out the algae. Both feed on the same nutrients. Have a place for the bacteria to grow, such as a bio-filter, rocks, plants, filter media.

      7. Both the barley straw and the bacteria will benefit from an aerator or provide some type of water movement. Increase circulation to the edges of the pond.

      8. Have pond at least 24" deep to reduce sunlight reaching the bottom

      Am a great follower of this website, which gives me with lot of information. You can you also take help of it. Hope it was useful. Please let me know if you more questions. http://www.naturalsolutionsetc.com

  12. >I would be interested in knowing what can be planted in the tank.

    Your tanks would have Diatom Algae, you just have to make them grow.

    The fertilizers and manure you use in the farm enter the water tanks and cause algae or weeds to grow. The blue green that is growing in the tanks is similar to the weeds that grow in your fields.

    In the fields you want a desirable crop to grow and keep out the weeds, so you use weedicides or other solutions to remove the weeds.

    What is the desirable crop in water ?
    Is it Blue Green Algae, Green Algae, Diatoms, Azolla, Duckweed, Water Hyacinth, etc.

    Unfortunately, not many have asked this question.

    The answer is Diatom Algae, these are the most prolific algae and account for about 50% of all photosynthesis in lakes and oceans. But in polluted ponds Blue Green Algae may dominate, especially in summer, due to excess nitrogen and Phosphorus in the water.

    Our product, Nualgi causes Diatoms to grow and thus keeps out BGA.
    Diatoms do not accumulate in the water, since they are consumed by zooplankton and fish, so you do not have to harvest them. This is the main difference between Diatoms and Blue Green Algae.

    Nualgi dosage for your tank would be about 100 ml per week.
    A one liter bottle will last you 10 weeks.

  13. Another thought, use a net covering entire pond in two - three peace and submerge the same in half fee down from surface. manually collect the algae by pulling net and use algae as organic fertiliser or soil conditioner or live stock feed.

    Alage benefit the water to purify ,.


  14. HI,

    How abt leaving some ducks in it?
    They use to mix it up the algae with water and it will not be stangnant on the water layers.

    1. What is the maintenance (feed, shed, etc) requirements for ducks? Do they need to be protected from cats, wild animals, etc?

  15. Did not think of this, probably a good time to get them in now as temperature is pleasant and get them accustomed by next summer.