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updatedAt: 2026-07-23T13:33:14.000Z
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# Supplementation and reinforcement

🌐 [🇫🇷 FR](https://wiki.myfood.eu/docs/carences-et-supplémentation) · **🇬🇧 EN** · [🇩🇪 DE](https://de.wiki.myfood.eu/docs/ergaenzung-und-verstaerkung)

Deficiencies lead to yellowing of the leaves.

Nutrient deficiencies cause diseases and also generate dead leaves that can encourage the appearance of insect pests.

> 📘 Guide to identifying pests, deficiencies and diseases
>
> [Open this guide to help you diagnose them by clicking this link.](https://myfood.eu/wp-content/MYFOOD-RECONNAITRE-CARENCES-MALADIES.pdf)

## 1. Diagnosis

You can use the descriptions below to identify a nutrient deficiency.

If you cannot clearly identify the situation, remember to take good-quality photos and share them on the Community, which will be there to help you.

## 2. Nitrogen deficiency (nitrates)

**Yellowing across the whole leaf**

The upper leaves between the older leaves and the young shoots are pale green.

Possible causes:

* Drops in temperature can harm the microbial population and therefore reduce the level of assimilable ammonia.
* You do not have enough fish in your system to produce ammonia.
* You are not feeding your fish enough; try feeding them more frequently and in smaller quantities.
* Your fish are not getting enough protein.

## 3. Iron deficiency

**Yellowing on young leaves and yellowing between the veins**

This is quite common in aquaponics but can be avoided fairly easily, which is why we recommend adding supplements every 2 weeks in summer and every 4 weeks in winter (3g, equivalent to one teaspoon / tank).

## 4. Potassium and magnesium deficiency

**Yellowing on older leaves and yellowing on the leaf edges, browning, spots**

Potassium, calcium and magnesium deficiencies can be difficult to distinguish from one another. When there is excess calcium or magnesium, you will most likely have a potassium deficiency. In addition, if you add shells to increase carbonates, we recommend adding 150g of potassium every 2 weeks in summer and every 4 weeks in winter (usage recommendations for the Family, 3 times less for the City).

## 5. Calcium deficiency

As mentioned earlier, these elements tend to compete with each other, which is why you must be careful when adding supplements. If you have a very low KH and you have added potassium, you may notice a calcium deficiency. The consequences include pests and black or brown spots on the tips of young leaves or fruits.

Calcium deficiency / apical chlorosis = blossom-end rot

Blossom-end rot is recognizable by a black spot that grows over time on the lower part of the tomato fruit. This is not a disease but a calcium deficiency.

* In aquaponics, add 100ml of calcium and 150g of magnesium every 2 weeks in summer and every 4 weeks in winter (usage recommendations for the Family, 3 times less for the City).

* In permaculture, avoid fluctuations between severe dryness and high humidity to better ensure the absorption of nutrients including calcium.

* Do not rush to remove the affected parts, since the unaffected parts of the ripe fruit remain edible.

* Prefer round tomato varieties over elongated varieties.

* Apply a thick layer of BRF to retain moisture.

* Add a few water stress indicator plants such as basil.

* Spray a calcium solution on the leaves at a rate of 5g/L (in permaculture).

## Add the supplements

* Dilute the components in 2-3 litres of hot water. Stir for 30 seconds. Let it rest for a few minutes.\
  Do not mix calcium chlorides with ammonium or magnesium sulfate as they may form precipitates.
* Shake again before distributing into the fish tanks.