What changes when you choose one?
Start with a sentence describing the need: “I need to supply a mineral nutrient,” “I am evaluating carbon supplementation,” or “I do not yet know why growth changed.” Those are three different decisions. Buying the more familiar bottle name will not resolve the third.
Seachem’s family guide separates the ordinary Flourish supplement from Excel, Iron, Nitrogen, Phosphorus and Potassium. Keep that distinction when reading a shop listing. A photograph or shortened title saying only Flourish is insufficient to identify which product is being sold.
Mineral nutrients
A declared analysis helps identify which elements the product supplies.
Organic-carbon role
The carbon role does not replace a mineral-nutrient plan or disclose a complete formula.
| Question | Flourish | Flourish Excel |
|---|---|---|
| Manufacturer’s stated role | Mineral nutrient supplement | Organic-carbon supplement |
| Useful published evidence | Nutrient analysis and derived-from list | Carbon-role description, directions and safety information |
| What this comparison cannot establish | Whether your tank lacks those nutrients | Whether carbon addition suits your plants and animals |
| Direct substitute for the other? | Different stated role | Different stated role |
Sources: Seachem ↗
What is actually declared in Flourish?
The current product page lists nitrogen, phosphate, potash, iron and several other elements. Selected figures appear below with the chemical labels preserved. Seachem explains that its analysis is a percentage by weight. A value on the bottle is not the concentration your aquarium reaches after adding it.
The company also says the ordinary Flourish product is not intended as a macronutrient supplement. If a planted aquarium needs more nitrogen or phosphorus, increasing a trace-oriented product until those rise also increases everything else in that mixture. Read the analysis before deciding what to add.
| Declared item | Manufacturer’s listed percentage by weight |
|---|---|
| Total nitrogen (N) | 0.07% |
| Available phosphate (P₂O₅) | 0.01% |
| Soluble potash (K₂O) | 0.37% |
| Iron (Fe) | 0.32% |
Sources: Seachem ↗
How much of the Excel formula is disclosed?
Excel’s product page describes an organic-carbon source. It does not present the same nutrient-analysis table as Flourish. Absence of an analysis on that page does not establish a zero concentration for every element, and it does not disclose a complete formula.
The linked safety sheet, revised September 1, 2022, includes a component entry and proprietary-information wording. That dated hazard document is not a complete fertilizer recipe or confirmation of the current regional formulation. For this purchase decision, use the stated carbon role and current product directions; do not infer a substitute from an online chemical name.
Does Excel replace injected CO₂?
Seachem positions Excel as a carbon option, but its own FAQ distinguishes it from carbon dioxide and describes different growth outcomes. That is a manufacturer explanation, not our comparative trial. There is no evidence here for converting a volume of Excel into a supposedly equivalent CO₂ concentration.
Plant choice matters. The current Excel FAQ flags sensitivity in Anacharis and reports Vallisneria responses at higher doses. It also warns that direct application or overdosing for algae control can damage plants. Use the actual product directions and obtain specific advice for sensitive plants. This comparison supplies no spot-treatment or higher-dose method.
Sources: Seachem ↗
Which alternative fits the missing function?
If you need a different mineral-nutrient profile, compare another fertilizer’s declared contents. For example, Tropica Specialised Nutrition explicitly includes nitrogen and phosphorus alongside other nutrients. That makes it a different composition to assess, not a universal upgrade or a bottle-for-bottle substitute. Its concentration, instructions and suitability still need a separate check.
A root-zone feeding method, a water-column fertilizer and a carbon system address different parts of a planting plan. Tropica’s plant-care overview separates those roles. Begin with the plant’s planting method, available light and nutrient supply. Our beginner plant selection helps you choose a manageable growth form before buying supplements.
Make one change you can assess.
Write down the exact products already in use, the plants affected, light schedule and recent maintenance. Photograph the same part of the plant over time. A new bottle added alongside a new light and substrate makes the outcome difficult to interpret.
Check the current label and manufacturer information before purchasing. Keep a dated record of the change and subsequent observations. If fish become distressed, use the fish-help checks promptly instead of interpreting the event as a fertilizer adjustment.
We compared the manufacturer’s stated purposes, declarations and cautions. We have not grown plants in a controlled comparison of these products. Selected percentages retain the manufacturer’s chemical labels; they are not dosing instructions.
- Seachem: Flourish product information and analysis ↗Role, selected guaranteed-analysis figures and by-weight basis. Manufacturer claims are not our independent performance measurements.
- Seachem: Flourish Excel product information and FAQ ↗Carbon positioning, distinction from CO₂ and sensitive-plant/direct-application cautions. No dose or growth-equivalence claim is adopted.
- Seachem: Differences between the Flourish products ↗Separates nutrient, carbon and individual element products in the product family.
- Seachem: Flourish Excel safety data sheet ↗Version dated September 1, 2022; proprietary information and hazard-document scope. No complete formulation or independent chemical identity claim is inferred.
- Tropica: Specialised Nutrition declaration ↗One documented alternative nutrient profile containing nitrogen and phosphorus. Not an endorsement, dose equivalence or universal suitability claim.
- Tropica: Plant-care overview ↗Separates nutrient supply, root-zone products, CO₂ and maintenance tools. Retailer recommendations and schedules are not generalized.
