Activated Carbon mixed into substrate

[faizal]

I can't seem to find the thread again but i remember reading somewhere that Mt Tom Barr once advised that we can use activated carbon mixed into the substrate as a carbon source for plants in a non co2 set up. This as a replacement for leonardite that Tom is famous for recommending as a carbon source for plants in a non co2 tank.

Is this the same activated carbon that we use in our filters?

 

[Yo-han]

Tourmaline BC from ADA is just powder of activated carbon. Try looking into that! Main things it does, it traps nutrients and releases it to the plant roots. It is a substrate for bacteria to grow on (apparently they grow better on this than on regular gravel for instance). Not sure the small amounts will be beneficial to the tank for long, but it won't hurt it either!

 

[ceg4048]

Faizal,
Tom might have meant something other than activated carbon being a source of carbon for plants. Plants only use carbon in the form of CO2. Activated carbon has no special properties to create CO2 unless electrical currents are used to ionize the carbon.

As mentioned, activated carbon actually has a higher surface area than some filter bio-media so it's fine to use as it removes and traps ammonia and other impurities which later, the bacteria feed on. So it's a source of carbon for bacteria because it will trap some types of soluble carbohydrates.

Cheers,

 

[faizal]

Tourmaline BC from ADA is just powder of activated carbon. Try looking into that!

Thanks Yo-han . So that's what tourmaline BC does! I am a bit out of funds for it though currently. So i might just go with the regular activated carbon mixed in at the bottom most part of the tank.

Faizal,
Tom might have meant something other than activated carbon being a source of carbon for plants. Plants only use carbon in the form of CO2. Activated carbon has no special properties to create CO2 unless electrical currents are used to ionize the carbon.

As mentioned, activated carbon actually has a higher surface area than some filter bio-media so it's fine to use as it removes and traps ammonia and other impurities which later, the bacteria feed on. So it's a source of carbon for bacteria because it will trap some types of soluble carbohydrates.

Cheers,

Cheers Clive . I guess i must have misread something somewhere. Was having premature high hopes for a few days & i was actually thinking of trying it out on another low tech . So that settles it then for me. So just to confirm this,...we CAN actually throw in some activated carbon miexd into the lower area of the substrate to help increase the aerobic condition of the substrate?

 

[dw1305]

Hi all,

So i might just go with the regular activated carbon mixed in at the bottom most part of the tank.

It won't do any harm, but it doesn't need to be charcoal, and it definitely doesn't need to be tourmaline. Adsorbent material like activated carbon (and to a lesser degree charcoal) hold other molecules via the weak physical "Van Der Waal" forces, but humic or clay compounds have a high CEC (Cation Exchange Capacity), and are potentially much more useful. Humic substances will also have AEC (Anion Exchange Capacity) under acidic conditions. Cation Exchange Capacity is the relative number of negatively charged binding sites on the surfaces of a substance (which bind positively charged ions cations like Mg++), the amount and nature of the cation bonding depends upon the lyotropic series. Anions are negatively charged ions like NO3-.

)So just to confirm this,...we CAN actually throw in some activated carbon miexd into the lower area of the substrate to help increase the aerobic condition of the substrate?

It won't make any difference. Any substrate layer, other than a very thin gravel one, will have fluctuating aerobic and anaerobic zones, but this isn't a problem. Have a look at these links <Substrate | The Skeptical Aquarist> & <Humic substances | The Skeptical Aquarist>.

cheers Darrel

 

[Yo-han]

Hi all,

It won't do any harm, but it doesn't need to be charcoal, and it definitely doesn't need to be tourmaline. Adsorbent material like activated carbon (and to a lesser degree charcoal) hold other molecules via the weak physical "Van Der Waal" forces, but humic or clay compounds have a high CEC (Cation Exchange Capacity), and are potentially much more useful. Humic substances will also have AEC (Anion Exchange Capacity) under acidic conditions. Cation Exchange Capacity is the relative number of negatively charged binding sites on the surfaces of a substance (which bind positively charged ions cations like Mg++), the amount and nature of the cation bonding depends upon the lyotropic series. Anions are negatively charged ions like NO3-.
It won't make any difference. Any substrate layer, other than a very thin gravel one, will have fluctuating aerobic and anaerobic zones, but this isn't a problem. Have a look at these links <Substrate | The Skeptical Aquarist> & <Humic substances | The Skeptical Aquarist>.

cheers Darrel

Agreed, a little correction: AEC generally will decrease when pH drops and increase when pH rises. CEC generally increases when pH drops and decrease when pH rises

 

[dw1305]

Hi all,

Agreed, a little correction: AEC generally will decrease when pH drops and increase when pH rises. CEC generally increases when pH drops and decrease when pH rises

You've got me wondering now, but I think I'm right, higher CEC in alkaline conditions? As pH increases, deprotonation increases, and H+ (& AL+++) ions are swapped for other cations? and the same in reverse for AEC, from the protonation of hydroxyl groups?

From "Soil quality considerations in the selection of sites for aquaculture..."
<Soil quality considerations in the selection of sites for aquaculture>

cheers Darrel

 

[Yo-han]

You're right, I mixed up acidity and pH, I'm sorry! As soil acidity increases (pH decreases), more H+ ions are attached to the colloids and push other cations from the colloids and into the soil solution (CEC decreases).