Aquarium macro and micronutrients: read the units and nutrient sources
By Richard James · Manufacturer sources checked · 28 October 2026
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Quick answer
Macro and micro describe the amounts plants require, not a ranking of importance. Identify the nutrient and reporting unit before comparing fertilisers or changing a routine.
Separate the categories
| Category | Examples / distinction |
|---|---|
| Mineral macronutrients | Nitrogen, phosphorus, potassium, calcium, magnesium, sulfur |
| Micronutrients | Iron, manganese, boron and other trace requirements |
| A product amount | Millilitres of liquid; not the mass of every nutrient |
| A test reading | A named substance in the sampled water |
What a product example establishes
Tropica distinguishes Premium from Specialised by nitrogen/phosphorus inclusion. The names “micro”, “complete” or “trace” cannot substitute for the declared analysis of a particular bottle. A micronutrient is not optional simply because the required amount is small.
A corrected volume example
If a reference amount for 10 gallons is added to 8 gallons of water, the amount per gallon is 10 ÷ 8 = 1.25 times the intended value: 25% higher, not 20%. A 20% reduction in water volume and a 25% increase in concentration use different denominators. This arithmetic alone cannot predict a later TDS rise or plant injury.
What should change the routine?
Use the exact label, actual water, existing inputs and a record of observations. A yellow leaf is not proof of one missing element. Read units and concentration and product strengths before converting a bottle percentage into a water concentration.
Sources and check scope
- UF/IFAS essential plant nutrient classification; botanical context, not an aquarium-dose guide
- Tropica Premium
- Tropica Specialised
Sources checked 28 October 2026. Botanical definitions and named fertiliser declarations checked; arithmetic reviewed separately; no livestock or deficiency diagnosis. This source check was assisted by AI; it is not an independent human expert or veterinary review. Match the exact pack and consult its manufacturer if directions conflict.