Filtration media

[fishshy]

Hi,
Just bought a canister filter with 4 trays inside. Need advice what are the suitable types of filter media to be used for planted tank.

[Aeon]

The water should go through the media in this order

Filter inlet <-----
|
|
V
Mechanical filtration
- Poly wool, ADA Palm Net, etc...
- Remove detritus like plant matter, food, shit, etc...
|
|
V
Activated carbon
- Remove excess ammonia
|
|
V
Biological filtration
- Bio balls, ceramic rings, etc, the more porous the better
- For bacteria to colonize
|
|
V
Filter outlet ----->

Since you have 4 tray, use the extra one for more biofiltration.
I read about this in Vol. 33 of Aqua Journal.

[MdmBudak]

Wool for mechanical filtration and sintered glass(Biohome, bioballs, EHFISUBSTRAT,etc) or ceramic rings for biological filtration.

If you are setting up a planted plant, suggest you not to use activated carbon. It will absorb the nutrients that you add for the plants and it has to be replaced regularly or else it will release all the toxins back into the water.

[bclee]

Like what I mentioned in the other thread... activated carbon do not remove ammonia.

BC

[Aeon]

[quote:9201f6029b="MdmBudak"]Wool for mechanical filtration and sintered glass(Biohome, bioballs, EHFISUBSTRAT,etc) or ceramic rings for biological filtration.

If you are setting up a planted plant, suggest you not to use activated carbon. It will absorb the nutrients that you add for the plants and it has to be replaced regularly or else it will release all the toxins back into the water.[/quote:9201f6029b]

As it is used only during the first stages, it is actually beneficial for reducing ammonia and absorbing excess nutrients. Nutrients are usually in excess during initial setups hence the usual algae growth during startups. After that the activated carbon can be replaced with more biomedia.

Activated carbon does remove ammonia.

[quote:9201f6029b="Aqua Journal vol. 34, Q&A page 34"]Q: Activated carbon is frequently added for chemical filtration. Will the activated carbon absorb essential nutrients required by aquatic plants?
Zia Jaffrey, New York City, USA

In a newly setup aquarium, large amount of toxins like ammonia and nitrate, which are harmful to the living organisms, will be present. Biological filtration will only be effective after the water have completed the nitrogen cycle. The whole process for detoxification requires about 2 weeks. During the interim period, activated carbon is often used to absorb the harmful ammonia and other chemicl toxins. You do have a point here. It's true that activated carbon not only aborbs harmful chemical components in the water, but it also absorbs nutrients needed by the plants. However, this minor drawback is not a major concern, since the activated charcoal is used essentially only during initial setting. Secondly, during this period when the aquatic plants are just beginning to acclimatise to the water conditions, limited nutrients are required. Any excess nutrients are in fact detrimental as algae will get to them before the plants do. Once the biological filtration has matured, simply replace the activated carbon with Bio-Rio biological media to increase the biological filtration capacity.
[/quote:9201f6029b]

[bclee]

You are right about carbon adsorbing (NOT absorbing) NH3. The NH3 can form bonds with C in the activated carbon.

In aquarium water, most ammonia exist as NH4+ ion which carbon has no affinity to. I am still in doubt of the adsorption mechanism of NH4+ adsorption to carbon. I am not sure how effective carbon is in aquarium adsorbing ammonia in the slight acidic conditions in our tank water. The NH3 molecules will now be NH4 ions. Now it will depends on the affinity of NH3 to H+ or NH3 to C (in the carbon). My feeling is that it will stay as NH4+.

Need to study more on that...

BC

[Aeon]

I believe activated carbon does not absorb by chemical raaction. else it would be 'remove'. I presume the ultra porous surface of AC traps and binds the ammonia molecules or something.

Need to study more also...

[bclee]

[quote:47dbeb44aa="Aeon"]I believe activated carbon does not absorb by chemical raaction. else it would be 'remove'. I presume the ultra porous surface of AC traps and binds the ammonia molecules or something.

Need to study more also...[/quote:47dbeb44aa]

Precisely, NH3 bond to C is a "physical" bond, whereas, NH3 bond to H+ forming NH4+ is a chemical bond. Activated carbon holds the NH3 by adsorption which is a form of physical bonding to the surface molecules. Porosity will greatly increase the surface area available for bonding.

Chemical bonding is usually stronger than physical bonding. That's why my suspicion is that ammonia will remain as NH4+ rather than being physically bonded to C.

BC

[budak]

I would just like to say that I have never used activated carbon for the last 3-4 years (except as a remedy for the runs ) and have never felt the need. Just stuff in the mechanical and biological filter media and that should be good enough.