Why is my aquaponics water green?

One common problem aquaponics practitioners face is the quality of water present in their system. Green water could mean algae's presence, which needs to be resolved immediately, or else there would be complications for the fish and plants. In this article, I will share how to deal with algae colonization in your aquaponics water.

What type of algae will grow in aquaponics?

Green algae are the most common type of algae in aquaponic systems. Moreover, if left unmanaged, these tiny organisms produce the most significant challenges and issues that could harm your garden.

You have probably seen green algae when you have tended a fish tank, a pool, or anything else with water. Green algae are multicellular and single-celled organisms containing chloroplasts (just like plants). Both species can be found in any aquaponics system.

Algae is a type of plant that consists of numerous different types of plant-like creatures. Algae come in different colors and textures, including slimy, bubbling, stringy, and even furious. However, all algae have the same light, air, and nutrient requirements. If the algae have this, they can grow quite quickly.

What are the effects of unmanaged algae in aquaponics?

Algae can proliferate anywhere in your aquaponics system. These can grow on or on the grow bed and in your tanks. Algae can cause problems in your aquaponics system if they are not controlled and handled, and I listed some examples below:

  1. Algae eat the nutrients that your plants would need.
  2. Algae can also restrict the amount of oxygen available to your fish, affecting their health and the overall performance of your aquaponics system.
  3. Algae can block your hoses, pipes, and pumps. This situation prevents water and nutrients from flowing across your aquaponics setup. Algae require oxygen to thrive, and because they live in water, they may extract dissolved oxygen from the water. Thus, lowering the amount of oxygen available to your plants.
  4. Algae can produce pH oscillations, which can harm the health of your system.
  5. Unmanaged algae will eventually cover the walls of your tanks and the roots of your plants, suffocating them.

How do you deal with algae in aquaponics?

There are two ways of dealing with algae in aquaponics. First is prevention, where you ensure that your system will not experience the adverse effects of algae growth. The second is management, and this applies when the algae have proliferated themselves, turning your water green.

Algae Prevention

Denying your aquaponics system any light is one practical approach to preventing algae growth. However, since fish and plants require light to survive, this can be a bit of a challenge to execute.

To keep the algae from growing:

  1. Try to keep as much light out of your system.
  2. Avoid using light-colored or clear grow beds and transparent tubings to achieve this.
  3. If you already have a clear grow bed, paint the outside black or cover it with black plastic to keep the light out.

You can also prevent algae from accessing growing nutrients. Here are some practical ways of achieving this:

  1. Adjust the flow of your water pump so that the water does not reach the top of the growing media.
  2. Allow no more than 1 inch of water to rise above the top of your growing media. This level is high enough for plant roots to reach the water yet low enough for the surface of the growing media to remain dry, preventing algae from colonizing.

Algae Management

Algae may still outsmart the aquaponics practitioner despite the efforts to prevent their rapid growth. When this happens, a series of steps may be taken to safely remove algae and bring back the health of your aquaponics garden.

  1. Cover your fish tank: You can cover your fish tank as you observe that algae are starting to grow. This step will not harm the fish but will deprive the algae of the necessary sunlight for growth. Additionally, covering the area will stop spores from spreading, eventually impeding algae development.
  2. Introduce algae eaters: Algae eaters can also do well in controlling algae growth in your aquaponics system. Shrimps and other fish species are the most prevalent algae feeders in aquaponics. On the other hand, these fish only eat algae during their early growing stages. They would prefer to eat plants as they grow older, so keep an eye on their development.
  3. Administer humic acid: To inhibit algae growth, humic acid can be administered to your aquaponics system. It is known to darken the water in your garden, thus denying sunlight to the algae and preventing it from growing. Humic acid is also a terrific addition to your system because it's suitable for fish and plants. It can even assist chelate several key plant nutrients.
  4. Install a UV filter tube: An UV filter tube should also be considered. This is similar to a little lamp that is submerged in water. The UV light emitted by the clarifier sterilizes the water in its vicinity. Because of this, the algal spores can no longer reproduce after the water has been sterilized. This process efficiently halts the growth of the algae while also safeguarding your aquaponics system.
  5. Remove algae physically: This step is the easiest since you are using your bare hands or simple cleaning materials to rid your system of the algae.
  6. Practice mechanical filtration: When it comes to algae removal, mechanical filtration is another effective option. A mechanical filter can be installed in the system, and it will remove the algae and spores. Filters, screens, settlement tanks, and other similar techniques for removing algae from the solution are part of the mechanical filter.

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