Seachem Flourish Excel Review

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seachem flourish excel bioavailable carbon review

If you’re an aquarist with a planted tank, then you know that adding CO2 can be essential for your plant’s health and growth. However, if you’re not interested in or able to set up a CO2 system, Seachem Flourish Excel may be a good alternative for you.

This product is designed to provide carbon to your plants in the form of dissolved organic matter. It also contains other essential nutrients for plant growth. In this article, we’ll discuss the benefits of Seachem Flourish Excel, how to use it, alternatives, and dosage instructions.

Seachem Flourish Excel Overview

There is a bigger picture you should visualize first before evaluating this product. In the center of that picture, is certainly CO2. This element, in the field of fishkeeping, is highly popular in planted aquariums due to the benefits which are directly connected to your plants and inevitably your fish.

seachem excel review

Since carbon for plants is basically their source of life, in an actual real-life scenario, they have quite a few natural sources to get carbon from, but in an enclosed space as a tank, they need external injections.

The Flourish excel is exactly that, a source of bioavailable organic carbon. This doesn’t make it equal to CO2 injection, but it makes it a healthy replacement or a strong combination. It’s good enough to bypass the involvement of CO2 in photosynthesis without the plant having to break it down, but instead, it gets a compound that’s finished and similar to CO2.

Now, on the Seachem page, you can find all this explained thoroughly and chemically. However, it’s just as good to understand that this product is a good addition to your CO2 compound but it is hard to say that it can replace it.

Some people swear by the effectiveness of injecting CO2 directly, but the Seachem Excel doesn’t interfere with that at all. Instead, it makes the whole operation ideal, especially since CO2 tends to lower a tank’s pH levels.

The Seachem Flourish Excel promotes the ferrous state of iron (F+3 to F+2, making it easier for plants to utilize) due to its iron-reducing properties. With all this technicality, it’s easy to lose track of its main purpose, which basically is providing carbon for your plants.

Flourish Excel Black Beard Algae Killer

Flourish Excel might also be used to remove Black Beard Algae from your aquarium. Black Beard Algae creates an unsightly film on the aquarium glass and can be difficult to remove. Seachem Flourish Excel helps to get rid of this algae.

flourish excel black beard algae killer

Features and Benefits

Certainly, the most deciding thing about a product is its features. And although you might think a carbon source can’t possibly excite you, there are a few features that will most certainly catch your attention.

Helps In Plants’ Growth and Health

Photosynthesis is how plants use sunlight to grow and create food, and CO2 is an important part of that cycle. Furthermore, several extended carbon chain molecules cannot produce without CO2.

Seachem Excel will speed up the photosynthesis cycle by assisting the plant in obtaining a comparable five carbon structure in a short time. This translates to faster photosynthesis and a boost for your plants’ growth and development.

Although not detrimental to your plants, you still need to watch out for the dosing since certain plants have specific needs. Without proper nutrition, your plants won’t be able to acquire CO2 resulting in their loss and unnecessary algae and ammonia in the tank.

With the right dosing and care, this product, given time, will achieve the greatest potential outcome.

Gets Rid Of Unwanted Algae

Although this product’s main purpose is to aid plants with carbon, it can do much more than just that. Getting rid of algae is just one of its many benefits. That means it can help with Black Beard Algae, which is troublesome to deal with.

It may effectively remove algae from rocks and plants (Black Beard Algae). You should proceed with caution while placing it in your tank in such a scenario. It’s best if you keep this in a separate container.

Fixes Iron

What this product basically does is that it enhances the condition of ferrous iron by removing one ion from ferric iron. Iron reduction is necessary for plants to remain healthy since instead of using additional ions in a more difficult operation, they tend to consume the ferrous one easier.

How to Use Seachem Flourish Excel

To dose something like this, you need to be consistent and precise. However, even if you forget one day or end up putting too much on another one, the Seachem Flourish Excel gives you the space to do that without endangering your fish. The chances are that probably won’t happen.

seachem excel flourish calculator

Now there are a few things to keep in mind, and we are going to explain them all below, but let’s see the big picture first. In our Seachem Excel review, we came up with some ground rules.

First of all, you will find two tables here that will make everything clearer. There are two ways you can go with the dosing.

  • One capful of 5ml per 50 gallons of water.
  • One capful of 5 ml for every 10 gallons.

This is quite a general dosing way and not very precise especially for people with smaller tanks. Therefore in our experiments, we used a drop as a way to dose it more accurately. Generally, for a 10 gallon tank, 100 drops will be okay.

In these tables, you’ll notice a dosage increase after the water changes. That’s recommended because a large water change will sacrifice quite an amount of CO2 and Seachem Excel. Some people think that’s efficient, some don’t. However, it’s good to experiment and find out what’s best for you.

Flourish Excel Dosing: Points to Keep in Mind when Giving a Dose

Before going an injecting Seachem Flourish Excel into your tank, keep in mind a few things:

  • The product lasts 12 hours.
  • It is not safe for mosses, ferns, and Val and is inefficient for slow-growing plants.
  • When you boost CO2 by adding Excel, to keep the levels, you may need to increase the amount of fertilizers you already put.
  • Because of the extra CO2 level, lightning intensity and duration will increase.
  • Be careful not to overdose and stick to a more precise measurement rather than the recommended one.
  • Don’t dose Seachem Excel directly on the plants. You can put it in your filter or the tank itself. However, dosing it straight onto your plants may damage them.

How to Remove Black Beard Algae with Seachem Flourish Excel

Does flourish excel kill algae? It does to that extent, that quite a few people use it as an algae killer instead of its main purpose. Although we answered vaguely earlier, there is a way to go around this in order to have the most efficient process possible.

black beard algae with shrimps

The main thing to keep in mind is to not overdose. Especially if you’re trying to cure algae, overdosing can lead to an explosion of algae rather than getting rid of them, so make sure to keep things under control for the most part.

A good way to start would be underdosing. By underdosing, a.k.a. almost halving the dosage, you give yourself space to experiment and see how everything goes. You kind of go with your gut after that and see exactly how this applies to your tank.

Quite a few people have actually overdosed and had their problem solved, while others had their algae multiply. So again, start slow and then build up from there until you see the algae disappear completely.


Now we can write many articles detailing just how perfect the Seachem Excel is as a product, but for some people, this product might just not cut it. And that’s okay.

For those who prefer something a little different, here are the alternatives for you.

API Co2 Booster

The key benefits of API Co2 Booster are the ability to gradually provide a supply of carbon compounds that are easily absorbable by your plants ensures that the health of your aquatic environment is preserved and it can be safely used in freshwater tanks with no risk of pH alterations.

api co2 booster review
API Co2 Booster
Best Co2 booster

Prevent algae growth

Safe to use


Daily use


Similar to other CO2 boosters, it provides an easier path for plants to deal with photosynthesis. Although not as complete as the Seachem Flourish Excel, this product is a solid option, but either way manages to provide the correct amount of CO2 in good timing to your plants. 1 ml is recommended for 10 gallons of water.

Careful: As with any co2 supplement, you need to take necessary precautions as this substance can be very irritating to the skin, eyes and even cause respiratory complications.

Brightwell Aquatics Florinaxis Carbon

If your main concern is the health of all the organisms living in your aquatic environment, you would love Brightwell Aquatics Florinaxis Carbon. The widely refined formula not only prioritizes and promotes the health and growth of both your fish and plants but also utilizes aerobic microorganisms to break down dormant organic material quickly.

brightwell aquatics florinaxis carbon review
Brightwell Aquatics Florinaxis Carbon
Best budget Co2 treatment

Provide Krebs cycle

Safe to use

Work great



The results it can produce for your plants and your aquatic pets are immaculate, and you will be at peace knowing that publicly detailed principles of biology back up the functions of this formula.

Rich in features, this one can be a tough nut to crack; however, it’ll be a breeze to go through with the detailed manual you get. During this Seachem Flourish Excel Review, if you thought that the Seachem didn’t do enough, this product would probably satisfy your needs.

The recommended dosing is 5 ml for the first 3 to 5 weeks of use for 50 gallons. You can then raise the dosing up to 250 ml for 2,500 gallons. In the manual, you will also find a more precise dosage with the drops method we used for Seachem.


If Seachem Flourish Excel has been on your radar for a while, then this review has made it clear for you. This product is well known and appreciated amongst planted aquarium owners and has served them faithfully. It offers a good alternative to CO2 injection without the need for a CO2 system or can be used in addition to it. Using it regularly will result in thriving your plants.

Even if you don’t think this is exactly what you’re looking for, maybe the API Co2 Booster or the Brightwell Aquatics Florinaxis Carbon can satisfy your tank’s needs. The latter for a more detailed approach, and the former for a solid alternative that covers the basics just as well.

In the end, have fun with it and experiment since none of these products is really expensive, and as we said way too many times now, be careful and do everything with regards to your tank.


If you’re wondering if Flurish Excel can kill algae or you want to know the difference between Seachem Flourish Excel vs Flourish, then read on for answers to these and other commonly asked questions.

Q: Does Flourish Excel kill algae?

It can kill algae, but it is not designed to be an algaecide. Seachem Flourish Excel should be used carefully if used for such a purpose. There are other products that are specifically designed to control and kill algae, like API ALGAEFIX Algae Control.

Q: What is the difference between Seachem Flourish and Flourish Excel?

There is a big difference between Flourish vs Flourish Excel. You can use Seachem Flourish to promote plant growth and increase the health of your plants. Seachem Flourish Excel is used by fish-keepers who have planted tanks in order to inject CO₂ into their tanks.

Q: Can you use Flourish Excel every day?

Yes, you can use Seachem Flourish Excel every day. You can use Seachem Flourish when needed without going overdose. Read the instructions on the label or the dosage calculator we provided for better usage.

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I am Mario, a experienced fish keepr and the editor-in-chief of Epic Aquarium.

At Epic Aquarium, we take our commitment to providing comprehensive and unbiased reviews very seriously. Our team carefully reviews each product, and we only recommend the very best in terms of quality. We also consult with leading fish keeper experts to ensure that each article is based on the most reliable and up-to-date information available.

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