Seachem Flourish Excel – Easy Carbon for Lush Planted Tanks (No CO2 System)

Lush Plant Growth Without a CO2 System

Aquatic plants need a carbon source to thrive, but pressurized CO2 systems are expensive, fiddly, and intimidating for many hobbyists. Skip the carbon and your plants stall while algae takes over.

Seachem Flourish Excel is a simple source of bioavailable organic carbon that plants absorb directly, so you get vigorous growth and stronger color without the cost and complexity of CO2 injection. It works on its own or alongside a CO2 system, and it's safe for fish and invertebrates like shrimp.

Flourish Excel comes from Seachem Laboratories, the science-driven aquatics company founded in 1979 in Madison, Georgia, where in-house chemists formulate every product. Excel is the carbon cornerstone of the coordinated Flourish planted-tank system, working hand in hand with the comprehensive Flourish supplement and targeted dosing of nitrogen, phosphorus, potassium, iron, and trace elements.

1. Shake and measure 1 capful (5 mL) per 50 gallons (200 L).
2. Dose daily or every other day; dose proportionately for smaller tanks.
3. Watch plants fill in greener and denser while algae loses its edge.

Give your planted tank the carbon it craves, no cylinder required. Add to cart.

What It Does

Delivers bioavailable organic carbon that aquatic plants absorb easily, accelerating growth, enhancing coloration, and helping plants outcompete nuisance algae. Suitable for all freshwater planted aquariums and safe for fish and invertebrates.

Directions

Dose 1 capful (5 mL) per 50 gallons (200 L) daily or every other day. For smaller aquariums, dose proportionately.

Why Seachem Flourish Excel

• Carbon cornerstone of the Flourish system: supplies the organic carbon that drives photosynthesis, the foundation the rest of the Flourish line builds on.
• Bioavailable organic carbon: plants absorb it directly, so growth accelerates without a pressurized cylinder or regulator.
• Fixes the carbon deficiency: the missing ingredient that stalls plants and lets algae take over in tanks without CO2 injection.
• Simple, proportionate dosing: 1 capful (5 mL) per 50 gallons (200 L), scalable to any tank size.

Best For

Ideal for low-tech planted tanks that lack pressurized CO2, where it delivers the carbon plants otherwise go without. It also complements high-tech setups as a supplemental carbon source, benefiting stem plants, carpeting species, and any greenery struggling to fill in.

FAQ

Do I need a CO2 system to use Excel? No. Excel is designed to provide bioavailable organic carbon without CO2 injection, though it also works alongside a CO2 system if you run one.

How does this fit with the rest of the Flourish line? Excel is the carbon source in Seachem's coordinated Flourish planted-tank system, pairing with the comprehensive Flourish supplement and targeted nitrogen, phosphorus, potassium, iron, and trace dosing.

How often should I dose? Dose 1 capful (5 mL) per 50 gallons (200 L) daily or every other day, dosing proportionately for smaller aquariums.