Plant nutrients:
All plants requires essential nutrients to grow:
Primary nutrient: Nitrogen(N), Phosphate(P), Potassium(K)
Secondary nutrient: Calcium(Ca), Magnesium(Mg), and Sulfur(S)
Micronutrient: Boron(B), Copper(Cu), Iron(Fe), Manganese(Mn), Molybdenum(Mo), Zinc(Zn), Chlorine(CI), Nickle(Ni), Cobalt(Co)
There's no perfect balanced fertilizer. Nutrients in aquarium change overtime, due to plant absorbed and precipitation.
Ph:
Ph affect nutrients availability to plants. When ph is 6.5-7.4 more NPK is available to plant. When ph is 5.4-6.0, more micronutrient is available to plants. Usually, plant grow tall and strong when all nutrients are fully utilized. However, it's always recommended to add less micronutrients than too much may cause algae issue.
Imbalanced nutrients:
This happen to all aquariums. People may have a nice planted aquarium from 2-3 months, with 1 month fully cycle period. Nutrient then gradually out of balanced, and deficiencies occur. This is "normal". Why? Nutrients is building up in the substrate overtime and when nutrients accumulating in the substrate they would prevent other nutrients uptake. It's recommend to vacuum substrate weekly to remove the nutrients in the root zoom to prevent nutrients build up.