Adding Nutrients To Aquaponics

Adding Nutrients To Aquaponics

Aquaponics combines raising fish and growing crops in a system and the fish waste serves as the plant’s nutrient. The plants also filter the water for the fish. However, sometimes the fish waste that serves as a plant’s nutrient may not be enough, and adding nutrients to your aquaponics system may be required.

This is why it is important you test your nutrient solution often to know if any nutrient addition will be necessary. This will help you prevent nutrient deficiencies in your aquaponics system. Adding nutrients to your aquaponics system when necessary will also boost the yield of your plants.

So, continue reading to learn about adding nutrients to your aquaponics system.

Aquaponics Nutrients

Nutrients are essential for plants growth and as we said earlier, the fish in your aquaponics provides these nutrients. The fish food you feed your fish usually contains all the appropriate nutrients required by your plants and it’s been supplied to your plants from the fish waste.

However, this fish waste may not contain the required nutrient quantity needed by your plants to grow efficiently. This is why supplemental nutrients may be required. So, adding nutrients to your aquaponics system is for the purpose of balancing the low level or low amount of nutrients provided by the fish food.

Aquaponics Nutrients


Before we look into adding nutrients to your aquaponics, the first thing to do is to test your nutrient solutions. This will help determine which nutrients are deficient and if they need nutrient supplements. Also, you will be testing for temperatures, pH range, and electrical conductivity. All these parameters need to be tested in your aquaponics system for nutrients to be absorbed appropriately.  There are different testing kits available for you to be able to do all this required testing.

  • PH Range

It is important for the pH level of your nutrient solution must be in range. This is required for optimal nutrient uptake by your plant and also for your fish survival.

If the pH level is out of range, plants will be unable to absorb nutrients appropriately. This is in turn causes the water to be polluted as this prevents the ammonia from converting to nitrates. It can also expose your fish to diseases.

  • Temperatures

When the temperature of your fish surrounding is too low or too high, it will cause your fish to become stressed. At the same time, it will affect your plants’ growth.

Inappropriate temperatures range can as well cause harm to the beneficial bacteria responsible for the conversion of ammonia to nitrates. When this happens, it can be quite detrimental to your aquaponics system.

  • Electrical Conductivity

Inappropriate electrical conductivity can slow the growth of your plants. Thus, decreasing the quality of your plant’s growth. It can also make the growth of your plant very fast which may be bad for some plants that will enter into the bolting phase quickly.

Electrical Conductivity

Aquaponics Nutrient Supplements: Adding Nutrients To Aquaponics

The most common nutrient deficiency that usually occurs in an aquaponic system is calcium, potassium, iron, phosphorous, and magnesium. These are part of the most essential elements required in your aquaponics system.

So, depending on the nutrient element missing, here are the following ways of adding nutrients to your aquaponics system:

  1. Calcium

The calcium deficiency can be solved effectively by spraying calcium solution over your plants. Mix calcium chloride with water and start with 4 teaspoons per gallon. Afterward, you can up the dose if need be. Ensure you spray once every week.

  1. Phosphorus

Using rock phosphate is one of the most easiest and common methods of adding phosphorous to your plants. Adding this supplement directly to your plant beds will allow for instant absorption. However, ensure you protect your plant bed from direct sunlight to get a successful result.

Adding shellfish bones to your fish tanks can also increase the supply of phosphorous as well as calcium.

  1. Potassium

Spraying and food additives are two ways of adding potassium to your aquaponics system. Spray potassium chloride onto your plants and repeat this process at least once a week. For food additives, add kelp meal concentrate to feed your fish. This will serve as a source of potassium.

TrueNute Potassium Silicate for Aquaponics, Hydroponics, Soil and Foliar Spray

  1. Iron

To supply iron to your plants, a type of iron that can be easily absorbed by your plant should be used. You can use chelated iron and one excellent type we recommend is the Fe-DTPA. When using this, ensure your pH range is 7.5 or lower.

Aquaponics Nutrient Deficiencies: Symptoms

The most common deficiencies that may occur in your aquaponics systems are that of potassium, calcium, iron, phosphorous, and magnesium. So, here are their symptoms:

  • Potassium Deficiency: the symptoms include wrinkled and cupped leaves and this is usually noticed in older leaves.

  • Phosphorous Deficiency: you may begin to notice the leaves’ veins turning purple color. Brown spotting on leaves and spindly growth may be another sign of phosphorous deficiency. Stunted growth especially during the early stage of plant growth can be another symptom of phosphorous deficiency.

  • Calcium Deficiency: deficiency in calcium will result in stunted growth and brown spotting on the young stem and on the leaves. You may also notice the leaves cupping and interveinal chlorosis. The plant that is a fruiting variety will exhibit blossom end rot.

  • Magnesium Deficiency: the symptom of magnesium deficiency is interveinal chlorosis that will begin from the older leaves. You may also notice some white to brown necrotic spots.

  • Iron Deficiency: deficiency of iron is very easy to discover. You will notice interveinal chlorosis on all the young growth of your plant. The severity of the interveinal chlorosis can be so obvious that it displays an almost white appearance in the affected plant area.


The most common nutrient deficiency in aquaponics is iron. Adding nutrients to the aquaponics system is mostly required in large-scale operations. This is because most aquaponics systems will do well on their own without requiring supplemental nutrients.

Always monitor the pH levels of your nutrient solutions so your plants can absorb nutrients appropriately.