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Seachem Laboratories Flourish Excel CO2 Plant Supplement - 500mL

Seachem Laboratories Flourish Excel CO2 Plant Supplement - 500mL


Item #: SC04530

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Flourish Excel™ is a source of bioavailable organic carbon. All plants require a source of carbon. This is typically obtained from CO2, but, may also be derived from simple organic compounds (such as photosynthetic intermediates). The use of either CO2 injection or Flourish Excel™ does not necessarily negate the use of the other. Because the processes of producing photosynthetic intermediates and building onto them occur simultaneously, one can derive a substantial benefit with the use of Flourish Excel™ either alone or in conjunction with CO2 . The combination is particularly ideal for situations when continuing to add CO2 could result in dangerously low pH levels. Flourish Excel™ also has iron reducing properties which promote the ferrous state of iron (Fe+2), which is more easily utilized by plants than ferric iron (Fe+3).

The reason plants need CO2 is to produce longer chain carbon compounds also known as photosynthetic intermediates. Photosynthetic intermediates includes compounds such as ribulose 1,5-bisphosphate, and 2-carboxy-3-keto-D-arabinitol 1,5 bisphosphate. Although the names are complicated, the structures are quite simple (5 carbon chains). Flourish Excel™ does not contain these specific compounds per se, but one that is quite similar. By dosing with Flourish Excel™ you bypass the involvement of CO2 and introduce the already finished, structurally similar compounds. It is in its structural similarity that Flourish Excel™ is able to be utilized in the carbon chain building process of photosynthesis. Simple chemical or enzymatic steps can easily convert it to any one to any one of the above named compounds (or a variety of others).

Directions for use:
On initial use or after a major (> 40%) water change, use 1 capful (5 mL) for every 40 L (10 US gallons). Thereafter use 1 capful for every 200 L (50 US gallons) daily or every other day. For smaller dosing please note that each cap thread is approximately 1 mL.

Manufacturer information

Seachem Laboratories, Inc. was established in 1980 by Dr. Leo G. Morin. Seachem moved into a state of the art 110,000 square foot facility in Madison, Georgia marking their 25th anniversary in the industry in 2005. This facility includes production and research laboratories, manufacturing, inventory, shipping, and office space.

5 Stars


Reviewed on
October 12, 2020

No, I would not recommend this.


Pros: none

Cons: doesn't work

Does't do much if anything to my planted aquarium. I have black beard algae in my 65 gal tank. For the past five years. I've tried taking out all my plants and used a bleach solution to kill the algae. And used Excel everyday. Every think looked good for about a week. Then it appeared again.
Been to many forums to discuss my problem and nothing works. I spent a small fortune on Excel over 5 gallons over the passed few years. The price has doubled since March of this year.
Don't waste your money. Big promises and no results.

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Reviewed on
November 17, 2017

Yes, I would recommend this.

Good stuff

Keeps my plants going strong. Use as directed

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valynda turner

Reviewed on
April 25, 2016

Yes, I would recommend this.


Plant looks more healthy.

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rimsky sucre

Reviewed on
August 15, 2015

Yes, I would recommend this.

I love this product.

I have been using this product for a couple of years. It has the benefits of CO2 and at the same time it keeps nuisance algae in check. I dose a capful every other day to my 80 gallon fresh water planted tank.

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brent mcclane

Reviewed on
October 10, 2011

Yes, I would recommend this.

Flourish Excel

I use this in cherry shrimp tanks that don't have CO2 and it seems to work great for me and doesn't seem to have any adverse effects on the shrimp. Highly recommend.

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michael upton

Reviewed on
March 08, 2011

Yes, I would recommend this.

Great Results

My plants have done very well with this product. I have fish and so cannot use carbon dioxide and this has been a great substitute.

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Reviewed on
May 11, 2010

Yes, I would recommend this.

good stuff

I wouldn't have a planted tank without it

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Reviewed on
April 10, 2010

Yes, I would recommend this.

kills algae, great for plants!

This is the holy grail of all products to use in a planted aquarium. youll get great growth and it will kill most algaes on the plants! Its a must for plants!

Was this review helpful? 6 0

stanley kurtz

Reviewed on
June 29, 2009

Yes, I would recommend this.

Brown/Black Algae

Used as an off label treatment, along with a phosphate reducer, killed off a stubborn brown/black algae infestation in my 55 gallon fresh water aquarium in 7-10 days, without injury to my fish. Will keep a supply of this around !

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Reviewed on
May 05, 2009

Yes, I would recommend this.

Quick carbon

I bought this to battle black beard algae that was taking over my Amazon swords. This was a stopgap until my CO2 system was set up. It worked pretty well and is fairly economical.

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