Richard bray

Nutrient Deficiencies/Toxicities
The most common nutrient deficiencies in an aquaponic system are:

• Nitrogen
• Potassium
• Calcium
• Iron

Nitrogen, potassium, and iron deficiencies all result in yellow leaves. However, they discolor in different leaf structures, which can help you differentiate between them. Increase fish feed to increase nitrogen.
A nitrogen deficiency will result in a leaf that yellows from the tip of the leaf down towards the stem. It can also result in stunted plants with thin, wilted leaves.
A potassium deficiency will result in a leaf that has yellow veins with green leaf tissue. This will also cause poor flowering and fruit set. Potassium hydroxide and potassium carbonate will both increase potassium, but they will affect the pH differently, so it's important to do a pH test before adding a potassium amendment.
A calcium deficiency will result in a leaf that is curled up and dry. This will also cause poor fruit set and blossom end rot. Calcium carbonate and limestone will help increase calcium, but these will affect pH, so it’s important to do a pH test before adding an amendment.
An iron deficiency will have yellow veins with yellow or white leaf tissue. Iron deficiency can mimic nitrogen deficiency, so it’s important
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to know how a leaf responds to iron or nitrogen deficiencies in order to add the correct amendment. Chelated iron is the only suitable amendment for iron deficiencies.
Insects
Traditional vegetable gardens have a diverse ecosystem of beneficial insects that keep pests at bay. However, an aquaponic system is such a controlled environment that it cannot support a diverse population of beneficial bugs.
This can allow a pest problem to get out of hand very quickly, which means prompt response is absolutely necessary for pest problems.
The most common aquaponic insects are:

• Aphids
• Caterpillars
• Mealy bugs

There are also many crop-specific pests that may infest your plants, which is why it's important to research crops before you plant them. Aphids, caterpillars, and mealy bugs can infest any crop at any time, which is why you must know what they look like and how to treat them.
The problem with insect infestations is that many insecticides have wetting agents that are extremely toxic to fish. Therefore, if you see signs of aphids, caterpillars, or mealy bugs, it is best to throw out any infested plants and destroy them.
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