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Discussion Starter · #1 ·
If I understand correctly (always an iffy proposition) the benefit of high CEC substrates (Flourite, Eco-Complete, fracted clay, etc.) it is that they have the ability to 'absorb' nutrients over time and that the roots of plants then have the ability to access these nutrients (minerals, ferts, whatever).

As I toy with various substrates and read more and more on the subject I have become curious if it is possible to 'pre-load' or 'soak' these substrates with fertilizers before inserting them in the tank.

Rather than dosing the water column (which is still needed in most cases with high growth anyways) and waiting for the high CEC substrate to 'absorb' nutrients over time is there a reason that it can't be done beforehand in order to start out with an already nutrient saturated substrate?
 

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If I understand correctly (always an iffy proposition) the benefit of high CEC substrates (Flourite, Eco-Complete, fracted clay, etc.) it is that they have the ability to '[STRIKE]absorb[/STRIKE] adsorb' nutrients over time and that the roots of plants then have the ability to access these nutrients (minerals, ferts, whatever).

As I toy with various substrates and read more and more on the subject I have become curious if it is possible to 'pre-load' or 'soak' these substrates with fertilizers before inserting them in the tank.

Rather than dosing the water column (which is still needed in most cases with high growth anyways) and waiting for the high CEC substrate to '[STRIKE]absorb[/STRIKE] adsorb' nutrients over time is there a reason that it can't be done beforehand in order to start out with an already nutrient saturated substrate?
fix'd:hihi:

and youre right...but in all honesty, it wont really matter in our tanks because we can make the nutrients as available as we want and plants dont care where they get them from

people grow beautifully lush tanks in aquasoil or in pure PFS...but the benefit of having it in the substrate is that you can stockpile nutrients in 2 places and miss dosing every now and then
 

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Discussion Starter · #4 ·
fix'd:hihi:

and youre right...but in all honesty, it wont really matter in our tanks because we can make the nutrients as available as we want and plants dont care where they get them from

people grow beautifully lush tanks in aquasoil or in pure PFS...but the benefit of having it in the substrate is that you can stockpile nutrients in 2 places and miss dosing every now and then
I was in a hurry and didn't have time to research whether they were 'adsorbing' chemicals (like activated carbon) or absorbing them. Thanks for the clarification.

Am I understanding correctly then that the amount of nutrients that they can adsorb (even at maximum adsorbtion or saturation or whatever) is only enough to supply nutrients for a short period of time at the rate at which our plant loads are uptaking said nutrients?
 

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depends on the plant and the speed in which they are growing

I would think that at full capacity...an enriched substrate can provide for your plants for a year or so

but we dont run our tanks at such high concentrations...so probably a week or so before you should add more nutrients
 

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fix'd:hihi:
Technically you shouldn't say "adsorbed" unless you know for a fact that the mechanism of binding the cation on the substrate is through an outer-sphere complex (with a water molecule in between the sorbent and sorbate). For a general description of cations binding on substrates the correct term is just "sorb", since the mechanism could be through outer or inner-sphere complexes. Just something that my soil chemistry professor beat into our brains and advised us to explain to other people when the term "adsorbed" was miss used :hihi:

But about the OP, I'd say it would just be easier to dose ferts on a regular basis, that way you are sure that your plants are getting the correct amount of nutrients on a regular basis.
 

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^^oh...ok:icon_neut

but my soil science and environmental engineering teachers did the same...drilled it into us because people using aBsorb and aDsorb interchangeably irritated them

aDsorbing is simply ions sticking to the face/surface (negatively charged face of the clay particles and the positive cations that plants use) of a different phase of matter -the mechanism isnt important...

sorbtion is a general term for either of the two processes

good try tho, but look it up

my school > yours :hihi::icon_cool:flick:
 

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^^oh...ok:icon_neut

but my soil science and environmental engineering teachers did the same...drilled it into us because people using aBsorb and aDsorb interchangeably irritated them

aDsorbing is simply ions sticking to the face/surface (negatively charged face of the clay particles and the positive cations that plants use) of a different phase of matter -the mechanism isnt important...

sorbtion is a general term for either of the two processes

good try tho, but look it up

my school > yours :hihi::icon_cool:flick:

:hihi: haha I did look it up before I posted it just to make sure I didn't look stupid haha. Adsorb describes a very specific process, one that binds an ion through an outer-sphere complex. You can find the definition in "Environmental Soil Chemistry", Second Edition by Donald L. Sparks (my professor). But yeah, my professor said that even scientists in the field do not use the term adsorb correctly--example, your teacher.

Anyway, where did you go to school? Cool to know that others on here share my interests of soils and agriculture.
 

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Discussion Starter · #10 ·
Technically you shouldn't say "adsorbed" unless you know for a fact that the mechanism of binding the cation on the substrate is through an outer-sphere complex (with a water molecule in between the sorbent and sorbate). For a general description of cations binding on substrates the correct term is just "sorb", since the mechanism could be through outer or inner-sphere complexes. Just something that my soil chemistry professor beat into our brains and advised us to explain to other people when the term "adsorbed" was miss used :hihi:

But about the OP, I'd say it would just be easier to dose ferts on a regular basis, that way you are sure that your plants are getting the correct amount of nutrients on a regular basis.
I wasn't looking to reinvent the wheel - just thinking out loud and trying to wrap my mind around some of what is going on in our tanks.

If there was some simple and easy solution I am sure that someone would have come up with it a long time ago - with all of the really clever stuff that people are coming up with I really doubt that something obvious would have slipped through the cracks. ;)
 

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fix'd:hihi:

and youre right...but in all honesty, it wont really matter in our tanks because we can make the nutrients as available as we want and plants dont care where they get them from

people grow beautifully lush tanks in aquasoil or in pure PFS...but the benefit of having it in the substrate is that you can stockpile nutrients in 2 places and miss dosing every now and then
alot of plants require fertile substrates over column dosing =p
 

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alot of plants require fertile substrates over column dosing =p
I'm 90% sure that is a myth. People look at the massive root systems some plants, like crypts and sword plants, have and just assume that those plants have to have nutrients available to the roots. But, that ignores the fact that roots are for different uses: to anchor plants in flowing water, to allow plants to grow emersed during dry seasons, and to provide nutrients. All plants can get adequate nutrients from the leaves, and all that have roots can also get nutrients from the roots.
 

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Does potato require more root nutrients than Basil?
It's got a big tuber structure.............the rhizomes of Crypts also have storage organs. Same for swords.

The larger the organ, the more likely it can survive harsh long conditions.

Most of these plants come from Rivers and streams where flow is high.
We also know that where these plants are from, every year the water level changes(a lot) and if there's no water........the plants will need roots to get water from the soil.

Terrestrial plants are often grown with nothing more than bark and sand in the pots, then they fertigate the leaves outdoors with sprinklers.

This is how about 90% of ornamental plants are grown in the USA. These are not even aquatic adapted. All plants can do this, and are opportunistic.

Cedergreen and Madsen(2001) have a good paper where they cut off the roots of the plants and they had the same rates of growth for 4 common aquatic weeds both with, or without roots in a nutrient rich stream.

Now..........if the water column is limiting and poor.........then soil is where the plants will go after the ferts then.

Now if you dose BOTH locations, now you have a back up for each location.
If you forget to dose here or there to the water, no biggie, and by dosing to the water....you provide longer life and supply from the sediment.
 
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