Seachem Flourish Excel 50ml What is Seachem Flourish Excel? Seachem Flourish Excel is a bioavailable organic carbon source for your aquarium. The treatment adds organic carbon, CO2 and chain carbon compounds to your aquarium to encourage plant growth. This makes it a great alternative to a complex CO2 injection system, though it can also be used in addition to one. Most importantly, Seachem Flourish Excel is completely safe for fish and invertebrates, when used correctly.How do I use Seachem Flourish Excel? Add one cap (5ml) of Seachem Flourish Excel for every 40L of water. This is a large dose and one that should only be added after initially setting up your aquarium or after a water change of 40% or more. For a smaller dose, add 5ml for every 200L of water daily or every other day. Note, each cap thread is approximately 1ml. Seachem Flourish Excel can also be directly dosed into your aquarium.Cyber monday. Get cyber monday deals here on cyber monday 2025. All the cyber monday sales and best cyber monday deals here.