Seachem Flourish Guide: The Ultimate Aquarium Plant Fertiliser Breakdown for Healthy Planted Tanks
If you’ve been searching Google for the best aquarium plant fertilisers, how to grow healthy aquarium plants, or a full Seachem Flourish dosing guide, you’ve just landed in the right place. The Seachem Flourish range is one of the most trusted planted tank fertiliser systems in the aquascaping world — but with so many bottles, it can be hard to know which one your plants actually need.
At Simply Fish, we use these products daily in low-tech, medium-tech, and high-tech planted aquariums, and this blog will walk you through every product, how to dose them, and insider tips to get the lushest growth possible.
Let’s dive into the complete Seachem Flourish guide.
🌱 Flourish Comprehensive — The Best All-Round Aquarium Plant Fertiliser
No matter what style of planted tank you run, Flourish Comprehensive (often searched as Seachem Flourish, Flourish fert, or best base fertiliser for aquarium plants) is where everything begins. This broad-spectrum supplement provides essential micronutrients, trace elements, vitamins, and amino acids — the building blocks of strong plant growth.
It’s ideal for:
-
Beginner planted tanks
-
Low-light aquariums
-
Community aquariums
-
Tanks with slow-growing plants like Anubias and Java fern
Use it once or twice a week and you’ve already covered most micronutrient needs.
💚 NPK Fertilisers — For Fast-Growing, High-Light, or CO₂ Planted Tanks
When people search “why are my aquarium plants pale,” “why are my aquarium plants melting,” or “best fertiliser for stem plants,” the answer is usually missing macros: Nitrogen, Phosphorus, and Potassium.
Seachem’s macro range is one of the most accurate and safest ways to dose NPK in a planted aquarium.
Flourish Nitrogen (NO₃ Fertiliser)
Helps fix:
✔ Pale new leaves
✔ Slow growth
✔ Nitrogen deficiency in stem plants
A must-have in bright lighting or CO₂ injected tanks where plants grow fast.
Flourish Phosphorus (PO₄ Fertiliser)
Fixes the classic issues like:
✔ Green Spot Algae (GSA)
✔ Stalled plant growth
✔ Faded leaf colour
Flourish Potassium (K Supplement)
One of the most common deficiencies in planted aquariums. Symptoms include pinholes, yellow edges, and declining older leaves.
Safe to use generously — potassium doesn’t trigger algae.
🔥 Iron & Trace Elements — For Red Plants, Carpets & Stem Plants
Searching for how to make red aquarium plants red, how to boost Ludwigia colour, or best iron fertiliser for aquariums? This is the section.
Flourish Iron
The go-to iron supplement for:
-
Red plants like Rotala, Alternanthera, Ludwigia
-
Fast-growing stems
-
CO₂ injected aquascapes
Daily or alternate-day dosing gives the deepest reds and strongest growth.
Flourish Trace
Perfect for high-demand tanks where plants burn through micros fast. Keeps colours crisp, stems strong, and new growth clean.
🌿 Root Zone Nutrition — For Swords, Crypts & Heavy Root Feeders
When people Google “best root tabs for aquarium plants” or “how to feed Amazon swords”, this is it.
Flourish Tabs
Loaded fertiliser tablets designed for:
✔ Amazon swords
✔ Cryptocoryne species
✔ Tiger lotus
✔ Large root systems
Use every 3–4 months for sustained root feeding.
Flourish Advance
One of Seachem’s most underrated products. Contains phytohormones that boost root development, increase nutrient uptake, and significantly improve plant recovery after trimming or rescapes.
💧 Flourish Excel — Liquid Carbon & Algae Control
One of the most searched products online:
-
liquid CO₂ for aquariums
-
how to kill black beard algae
-
CO₂ alternative aquarium
Excel is a liquid carbon source that improves plant growth AND doubles as a powerful algae spot treatment.
But note: Vallisneria, Anacharis, and some mosses can be sensitive.
🧪 Which Flourish Products Should You Use? (Based on Tank Type)
If you’ve ever searched “best fertiliser schedule for planted tanks” — here’s the quick breakdown.
🌿 Low-Tech Aquarium (No CO₂)
-
Flourish Comprehensive — weekly
-
Potassium — weekly
-
Flourish Tabs — every 3 months
🔆 Medium-Tech Aquarium (High Light, No CO₂)
-
Flourish Comprehensive — 2× weekly
-
Potassium — 2× weekly
-
Iron — weekly
-
Excel — daily
🚀 High-Tech Aquarium (CO₂ Injection)
-
N + P + K — 3–6× weekly
-
Iron — daily
-
Trace — 2× weekly
-
Advance — every other day
-
Flourish Tabs — every 2–3 months
💡 Pro Tips for Using the Seachem Flourish Range (From Real Store Experience)
Straight from the Simply Fish team — the stuff we tell customers every day:
-
Dose macros (NPK) in the morning & micros (Iron, Trace) at night to prevent nutrient binding
-
Excel is most effective dosed at lights-on
-
Weekly water changes reset your nutrient balance
-
Shake every bottle — especially iron and potassium
-
Spot-treat black beard algae by turning off your filter and applying Excel with a syringe
-
Replace root tabs before plants decline, not after
-
Consistency is king — especially in CO₂ tanks
🎉 Final Thoughts — Why the Seachem Flourish Range Works So Well
The reason the Seachem Flourish fertiliser system is so popular is simple:
It’s flexible, accurate, and perfect for any planted aquarium — from a beginner’s 40L tank to a high-end aquascape.
When you understand what each product does, you can choose exactly what your plants need, avoid algae problems, and grow the kind of tank that gets people asking, “What’s your secret?”
If you want help setting up a personalised Flourish routine for your tank, just pop into Simply Fish or message us — we work with everything from betta tanks to monster aquascapes every week.