# Does Seachem fluorite black gravel lose nutrients?



## mfurufuru (Mar 20, 2012)

From what I've read it is actually rather inert as in it contains no nutrients. Flourite is fracted clay and supposed to be good for its ability to capture nutrients and retain them for plant roots (CEC). So if you use root tabs the flourite will absorb the nutrients and become charged. I assume fish poop and decaying plant matter also provide the same effect.


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## Monster Fish (Mar 15, 2011)

It has no macro nutrients. As mfurufuru said, it's used for CEC so you will need to dose to get the most use out of it.


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## Zapins (Jan 7, 2006)

Fluorite should be considered inert. It will not help provide nutrients to your plants in any substantial way. It is simply a nice looking and heavy substrate.

If your plants have slowed down they may be suffering from a nutrient deficiency of some kind. Please post a few photos of the plants (close up ones) and let us know what fertilizers you are adding and how often.


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## Diana (Jan 14, 2010)

Substrate is like the dinner plates on your table: It will only hold the food you put on/in it. 

Some substrates will come in the bag with a limited supply of fertilizers, but you need to keep fertilizing to keep up the fertility. 

Like a dinner plate after you have eaten all the food. It is still useful, but you need to add more food.


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## Ethana (Jun 13, 2013)

Thanks a lot guys, this is really helpful, I'm going to get some macro fertilizers.
Then my tank should get rolling


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## Seattle_Aquarist (Jun 15, 2008)

Ethana said:


> Hey,
> I've had this stuff in my tank for about 2 years and I've noticed a couple of my plants growth slow down a lot in the past 6 months.
> Is this possible?
> Ethan


Hi Ethan,



> 19. Flourite - Seachem, USA - fracted, stable clay; very hard; multi-colored (brown, red-brown, black); resembles aquarium gravel; no organic matter


Flourite is indeed inert, in that it contains no organic material. Nor does it have a high cation exchange capacity (CEC = 1.7) compared to the Montmorillonite clay products (Turface, Safe-T-Sorb #7941, kitty litter) with much higher capacities (CEC = 27-41) so the ability to Flourite to absorb nutrients from the water column and release them to the plant root zone is minimal. However, Seachem Flourite does contain good levels of a multitude of minerals that plants need for growth including iron, magnesium, manganese, zinc, and several others and those nutrients are available to the plants.

There was an excellent article comparing many substrates in the summer 2000 issue of _Planted Aquaria_ (predecessor of Aquatic Gardener's Association current newsletter _The Aquatic Gardener_).

All that said, what is the cause of your diminished growth? Although it is possible that the Flourish has had a nutrient depleted I would look into other possible causes first such as KNO3, KH2PO4, CSM+B, Fe, Mg, and others. Also, I find my growth rate changes if I don't change the bulbs annually in my fixtures.


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## Zapins (Jan 7, 2006)

A great summary of fluorite Seattle_Aquarist.



Seattle_Aquarist said:


> However, Seachem Flourite does contain good levels of a multitude of minerals that plants need for growth including iron, magnesium, manganese, zinc, and several others and those nutrients are available to the plants.


For perspective, while fluorite does contain these nutrients I do not believe they are actively available to the plants in any significant way. The analysis of fluorite is done by crushing the product up into powder and then dissolving it in water so it can be run through an analysis machine. This is very different to what plants are exposed to when planted in fluorite. The amount of surface area the roots are in contact with is miniscule compared with a powdered solution of the substrate.

Keep in mind that rocks in the garden contain high amounts of trace minerals as well, but having a garden made of 100% rocks won't grow you plants.


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## Diana (Jan 14, 2010)

Sort of like grinding up your dinner plate and saying it has plenty of vitamins and minerals.


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## Zapins (Jan 7, 2006)

Diana said:


> Sort of like grinding up your dinner plate and saying it has plenty of vitamins and minerals.


Haha, I like your dinner plate analogy!

They used to make some types of fine china using bones as a major ingredient, so who knows perhaps grinding up plates will catch on!


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## Behike (May 27, 2014)

Diana said:


> Substrate is like the dinner plates on your table: It will only hold the food you put on/in it.
> 
> Some substrates will come in the bag with a limited supply of fertilizers, but you need to keep fertilizing to keep up the fertility.
> 
> Like a dinner plate after you have eaten all the food. It is still useful, but you need to add more food.



I like your analogy! Good one! 


Behike


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