Seachem Flourish Excel – Liquid Carbon Supplement & Algae Control

Flourish Excel provides bioavailable organic carbon essential for plant growth. It can be used alone or with CO2 to benefit plant growth, especially in situations where adding more CO2 could lead to low pH levels. Additionally, Flourish Excel has iron-reducing properties that promote the utilization of iron by plants. By bypassing the need for CO2, Flourish Excel introduces structurally similar compounds that support the carbon chain building process of photosynthesis.

Key Benefits of Seachem Flourish Excel

• Provides a bioavailable carbon source for aquatic plants

• Promotes stronger, healthier plant growth

• Helps control nuisance algae naturally

• Perfect for aquariums without CO₂ injection

• Safe for use with fish, plants, and invertebrates

• Easy to dose & highly effective

How We Use It at Horizon

At Horizon Aquatics, we primarily recommend Flourish Excel as a targeted algicide rather than a long-term replacement for a CO₂ system. It’s excellent for spot-treating algae on hardscape or plants, but caution is advised when using it daily as a carbon source.

Some delicate species are sensitive to Excel and may be damaged by regular use. For example:

• Grass-like plants such as Vallisneria can “melt” when exposed to higher doses.

• Certain fully aquatic plants like the Tiger Lotus (Nymphaea lotus) are also known to react poorly.

For this reason, we suggest using Excel carefully and monitoring your aquarium’s plant health closely. Sensitive plants like vallisneria, riccardia moss, lotus species, we use APT FIXlite as an alternative. 

Available Sizes & Water Treatment Capacity

• 100 mL – treats up to 2,000 L

• 250 mL – treats up to 5,000 L

• 500 mL – treats up to 10,000 L

Directions for Use

• On initial use or after major water changes (>40%): 5 mL per 40 L.

• For daily dosing: 5 mL per 200 L.

• Can be used in conjunction with CO₂ injection for even greater results.

DO NOT OVERDOSE