# Flourite vs Dark vs Black vs Red



## UnicornStampedes (Jul 7, 2015)

Hey all 

Substrate nub here need your haalppp.

I am looking to get Flourite substrate and I was wondering if the differences between the different kinds of fluorite subs would have a huge impact on the plants? I know that fluorite is supposed to be inert but then there's all these numbers... and some are significantly higher/lower than others... Should I pay attention to these or not? I also wanted to know if all of them have the same CEC and if not, which one has the highest?


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## Hoppy (Dec 24, 2005)

Flourite is an inert substrate. The different colors are different because of their chemical composition, but they are all still inert. Plants are color blind, when it comes to the substrate.


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## UnicornStampedes (Jul 7, 2015)

I guess I was more asking for instance on the regular flourite it has 18,500 Iron whereas flourite dark has only 5,326. which of all these differences matter to plants? would the one with higher iron be better etc


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## Patriot (Dec 22, 2010)

That does look interesting. I thought they were all the same. I guess if you wanted more red plant you would pick the one with more iron for example.


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## Hoppy (Dec 24, 2005)

Iron compounds in the minerals that make up Flourite are only barely available to the plants. They have to be chemically altered by bacteria in the water or they are locked up in the substrate particles. So, it makes no difference which color you use. To get more iron available to the plants just dose CMS+B or an equivalent trace element mix.


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## mysticalnet (Dec 2, 2007)

I don't think they are inert. It's like saying plastic bottles are inert, but we keep hearing about certain types of plastic slowly releasing PCBs or BPAs. 

The only inert things we can safely say are gold, diamond, platinum....

I vote for fluorite slowly releasing nutrients and not completely locked up. Especially with time, bacteria and constant water contact.

Given that, the releasing rate is probably too slow therefore you would need to fertilize in the water column and have root tabs.


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## UnicornStampedes (Jul 7, 2015)

Thank you for all of your responses.

So what I've taken from this is that Flourite is _not completely inert_ but inert enough that I would have to add ferts/CO2 for my plants to thrive and the chemical composition is pretty much irrelevant for the same reason so just pick which colour I want? 

*Also if anyone knows which of the flourite substrates have the highest CEC? I was mainly only considering flourite/eco-complete and the like because of their CEC otherwise I would have just gone for a completely inert substrate*


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## mysticalnet (Dec 2, 2007)

CEC as in the cation exchange capacity? It's hard to determine that from just the chemical composition supplied of the substrate, you'll need to send a small sample of each substrate to a local lab that does CEC to give you those values. It's a relatively simple test and they spud be able to give you results in a few days.

Also your chart has no units for the numbers.


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## Hoppy (Dec 24, 2005)

Granite is typically 2-3% iron. Does anyone think that putting crushed granite in the substrate would supply the iron needs of the plants? Of course nothing is totally inert, but, as far as plant available nutrients are concerned, both granite and flourite should be considered inert - not a source of nutrients for the plants.


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## UnicornStampedes (Jul 7, 2015)

Then how come people swear by flourite and eco-complete and such? if these substrates really don't provide much, how come people dont just pick your typical inert gravel/sand? is it only because of flourite's/eco-complete's CEC? and if so, does that justify purchasing them over gravel/sand?

as for the seachem black and onyx sand... do these have high CEC as well and will be able to grow plants?


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