Do You Need To Change The Water In An Aquaponic System?

Aquaponics is an innovative method of growing fish and vegetables in the same system, and there are many benefits associated with this type of farming. While it’s important to maintain a certain quality of water so the plants and fish stay healthy, some aquaponic systems require water changes to keep the environment balanced.

In this guide, we’ll discuss how often you should change your aquaponic system’s water, what factors can affect this number, and tips for keeping your system healthy and balanced even if you don’t need to do regular water changes.

What is an Aquaponic System?

An aquaponic system is a self-sustaining system where fish and plants are combined in an eco-friendly and efficient way. Fish waste is broken down by bacteria and used as fertilizer for plants, while the plants filter out the waste and clean the water for the fish. This type of system is a great way to grow plants without the need for chemical fertilizers or other input from the grower.

In this article, we’ll discuss the basics of an aquaponic system and how it works:

Components of an Aquaponic System

An aquaponic system is a combination of both aquaculture, which involves the raising of aquatic animals such as fish or shellfish, and hydroponic horticulture – the growing of plants without soil. This basic design usually includes a re-circulating tank that houses fish and other aquatic animals, while connected to it is a hydroponic bed or other similar type component where plants are grown.

Aquaponics systems come in all sizes and some of the components may vary depending on their design. Generally speaking, however, these are the core components of any aquaponic system:

  1. Aquaculture System: This re-circulating tank houses aquatic animals like fish or shellfish. Its size will depend on the size and type of system that you have chosen to install.
  2. Hydroponic System: This component can be anything from a standard grow bed to specialized media beds for rooting plants such as lettuce and tomatoes.
  3. Biofilter: The biofilter is responsible for breaking down toxic ammonia produced by their aquatic inhabitants into much less toxic nitrates, which are then used by the plants as fertilizer for growth.
  4. Sump Tank: The sump tank is used to store excess water that needs to be drained from the system depending on usage cycles or extreme weather conditions like flooding or drought.
  5. Air Pump & Air Stone: An air pump and air stone are necessary components in an aquaponic setup because they aerate the water in an effort to keep oxygen levels high enough for healthy fish growth as well as fostering natural filtration processes within your environment.

Water Change Requirements

Aquaponic systems rely heavily on maintaining clean, healthy water. Water quality is typically monitored with nitrate and ammonia tests, and if these levels get too high, it is time to perform a water change. It is important to understand how and when to do a water change in an aquaponic system in order to keep it running smoothly.

Let’s look more closely at water change requirements in an aquaponic system:

Frequency of Water Changes

Aquaponic systems require a regular water change schedule to keep the system functioning properly, due to the buildup of nitrates and other pollutants in the water. How often you will need to change the water in your system will depend on its size, how many fish are present, how much solid waste is entering the system, and how often you clean the filters.

As a general rule of thumb, most aquaponic systems should be cleaned out by performing a complete water replacement at least once every three months. The exact frequency may vary depending on the conditions in your specific system; larger and more heavily stocked systems may require more frequent changes than smaller ones. If you think that water changes are necessary more often than every three months, it is best to contact a professional aquaculture expert for advice.

In addition to changing out a portion or all of your aquaponic system’s water periodically, regular maintenance is also key to keeping it running smoothly. This includes

  • cleaning filters and pumps,
  • topping off evaporated water levels,
  • checking pH levels regularly, and
  • testing ammonia levels at least once a week – ideally twice per week.

Monitoring these vital measurements can help prevent issues related to an unbalanced environment within the aquaponics tank before they become major problems.

Reasons for Water Changes

Aquaponic systems use a blend of fish, bacteria and plants to create a source of food production that is profitable and sustainable. To maintain the health of any aquatic system, regular water changes are recommended. These serve several purposes:

  • To remove decaying solid waste as well as dissolved solids which can disrupt the delicate balance in an aquaponic system;
  • To replace essential minerals; and
  • To reduce ammonia levels from fish waste.

Depending on the size of your tank and its inhabitants, water changes can be done on a daily, weekly or monthly basis. You may want to consult with an expert to help determine an appropriate schedule for your particular tank. It is important to remember that water changes should be gradual and done carefully over time to provide adequate time for bacterial colonies in the aquaponic environment to adjust without interruption or shock.

Benefits of Water Changes

Regular water changes are important when maintaining an aquaponic system. This can help to maintain the optimal level of ammonia, nitrates, and nitrites in the water. Furthermore, regular water changes can help to remove any bacterial or fungal build up and ensure a healthy environment for your aquaponic system.

Now let’s discuss the benefits of water changes in more detail:

Improved Water Quality

One of the most important reasons to do regular water changes in your aquaponics system is to maintain optimal water quality. Unchanged water’s pH level can fluctuate, upsetting the balance necessary for healthy fish and plant growth and causing algae blooms that can be toxic for aquatic life. Changing the water on a regular basis ensures overall better aquarium environment health and eliminates build up of sediment, metals, nitrates and other particles that may build up to bad levels in recurrently used water.

In addition, some advocate that partial changes which replace only a portion of the original aquarium water with fresh will help keep high oxygen levels as well as prevent dangerous levels of toxins from accummulating. Additionally, if you have added fertilizers or booster supplements such as potassium carbonate or phosphorous compounds these compounds may need to be neautralized periodically or they will have a negative impact on the system’s inhabitants. By controlling the quality and composition of your pond environment through timely partial replacements you will ensure good health for both your plants and fishy residents. Lastly, exchanging out the old water helps expel old ammonia buildup whilst incubating an ideal pH range – which makes it easier for beneficial nitrifying bacteria to break down proteins into usable forms by nitrifying bacteria within your system’s bio filter or media bed filter or other aquaculture machines employed in an aquaponic setting. Also checkout Do Aquaponic Fish Need Sunlight.

Ultimately regular water exchanges can:

  • Reduce maintenance time in other areas – such as cleaning tanks regularly – further lowering upkeep costs by helping prevent sludge buildup from occurring over time;
  • Potentially improving clarity, odor and aquarium aesthetics;
  • Reducing stress on tank inhabitants;
  • Promoting healthy growth for both plants via more oxygenated stewed liquids;
  • Enhancing fish metabolism;
  • Improving edible vegetation flavors by adjusting mineral concentrations;
  • Keeping disease outbreaks under check by preventing pathogens from thriving amidst deteriorating conditions – all while maintaining safe conditions conducive to healthy living throughout the entire tank eco system set up!

Reduced Algae Growth

Do you need to change the water in an aquaponic system?

Regularly changing water in an aquaponic system can help keep your fish and plants healthy by reducing levels of nitrates, ammonia, ATP and other contaminants. Changing the water also reduces the risk of algae growth, which can clog the system, block sunlight from reaching the plants, and make it difficult to maintain oxygen levels.

By diluting toxic levels of nitrates, phosphorus and other minerals on a regular basis through water changes, you help to ensure that the beneficial bacteria in your system remain healthy. As an added benefit, regularly changing water helps keep pH levels stable without chemical intervention or reliance on expensive pumps.

The amount of water changes needed varies depending on your setup as well as factors such as light exposure/plant type; plan to change 10-20% every week or 20-30% every two weeks. When performing a large water exchange it is important to match temperature and salinity between old and new waters in order to minimize stress on both fish and plants. Monitor nutrient levels before and after the change so that you can be sure that any needed adjustments have been successful.

Increased Nutrient Availability

When the water is changed in an aquaponics system, the water’s chemical composition, which includes its pH, nutrients, and mineral content, is altered. Increased nutrient availability can promote better growth and help to restore the balance of oxygen, nitrates and other important compounds. The influx of fresh water can also increase levels of dissolved oxygen in the system, which is essential for healthy fish since it upgrades their metabolic rates.

Furthermore, as waste accumulates at the bottom of tanks or reservoirs over time—it can become toxic to both your plants and fish—a full water change helps to lower these levels by removing a percentage of those toxins. Regular water changes also allow you to replace trace elements that are deficient in the system’s existing environment by introducing them with extended treatments such as Epsom salts or certain aquatic products like tissue builder.


In conclusion, water changes are an important part of keeping your aquaponic system in balance and ensuring that your plants and fish remain healthy. Regular water testing and checking pH levels is key to a successful aquaponic system and considering how crucial it is to the success of your system, you should definitely plan on changing the water regularly.

However, how frequently you need to change the water in an aquaponic system varies depending on your size and setup. A larger system naturally has its own nutrient cycle, while a smaller one needs to be replenished regularly. Keep testing and adjusting as per manufacturers’ instructions for optimal results.

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