Mineral deficiencies can be detected by observing the plants and their symptoms.
Magnesium, nitrogen, phosphate, potassium for example are mobile nutrients and calcium, iron are immobile.
Mobile nutrients can be moved within the plant to avoid a shortage while a deficiency in immobile nutrients has an instant effect on the plant.
Signs of deficiencies:
|Old leaves turn yellowish/ red||Nitrogen deficiency|
|Old leaves turn yellowish/ red; Leaf loss and small dead areas||Phosphate deficiency|
|Black/ brown leaves, plants die||Excess phosphates|
|Yellow spots on old leaves and yellowish margins on younger leaves||Potassium deficiency|
|Yellowish margins on young leaves with deformations||Calcium deficiency|
|Yellow spots on old leaves while veins stay green||Magnesium deficiency|
|Young leaves turn yellow||Sulfur deficiency|
|Yellowing leaves starting from the tip then become transparent||Iron deficiency|
|Yellow spots between the veins, margins and tips||Zinc deficiency|
|Plant stays small slow or now growth white deposits on leaves (calcium)||CO2 deficiency|
|Fish gasp for air on surface||Excess CO2|
|Sluggish fish no plant growth||Oxygen deficiency|
|Plants stop growing/ black roots||Substrate problem|
Carbon Dioxide (CO2)
A possible source for a CO2 deficiency can be a well aerated tank. Airstones or high surface turbidity can diffuse the CO2.
Excess CO2 can be a result of poor lighting (the better the lighting the easier, the CO2 uptake of the plants), or an over fertilization of CO2.
The substrate is either to loose or compacted. If agitated gas bubbles can be detected on the the surface. This is also an indication that the substrate is old and in need of replacement.
Plants will stop growing and die off if the water is to cold. Higher temperatures will result in smaller leaves and larger gaps between these leaves.
Light is essential for photosynthesis. Not enough wattage or aging bulbs will stun the plant growth. Plants look weak with small pale green leaves. Plants closer to the light will be less effected.