Some info about AC

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ACTIVATED CARBON...probably one of the best weapons of chemical filtration and possibly one of the least understood. There are several different materials used to make activated carbon (AC). Probably the most common is bituminous coal. Lignite and coconut shells are also used. The base product is heated to about 900 deg F. This first heating is done with no air. This results in the material being charred. Then, it is heated a second time with air to a temp of about 1600 deg F. The remaining hydrocarbons are removed with this step and lots of tiny passages and holes are left in the carbon. It is now "activated".

The carbon is much like a sponge...large holes on the outside lead into smaller and smaller passages on the inside. Basically, through a process called adsorption, molecules enter the large holes and are eventually trapped as the passages get too small for them to travel any further. Single molecules can enter through the smaller pores while the larger pores allow complex molecules to enter.
A few examples of the stuff that the carbon will remove ...iodine, phenols (yellow water), amino acids, copper, chromium, iron, mercury, chlorine, chloramine, hydrogen sulfide, sulfa, and antibiotics.
AC can't remove ammonia, nitrite, and nitrate.

How do you tell whether you're getting good carbon?

First, make sure the container says "Activated Carbon". Some of the cheaper carbon may be plain anthracite coal. A dull black color is preferable to a shiny appearance. The dull color indicates a higher porosity. A rounded particle will enhance water flow and therefore is preferable to a flat sided particle. Another indication that you have a good grade of carbon is, when submerged in water, it gives a hissing sound as the cavities fill with water. It should also float at first...sinking slowly.
Secondly, look for labeling that states that the carbon is "phosphate free".

The most effective use of carbon in the aquarium is to have it in a bag in a place where it receives a constant slow flow of water, or place AC in reactor with a small powerhead. Blasting the carbon with the stream from a high powered pump can wash the contaminants right out of the carbon.


How long will it last?

Impossible to accurately predict. A good system to start with is to have two bags of carbon in the system and change one every3-4 weeks and better to change it more often because the carbon, upon reaching saturation, can begin to leach the compounds back into the water. It's especially important to change the carbon quickly if you've used it to remove antibiotics or other medications from the water.
If you see that water is turning a yellowish color, then it is time to have replaced it.
 
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Nice one Lanzo, first time i've seen this thread!
 
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Thanks Lanzo
 
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Really good read. Thanks lanzo

Where would be the ideal place for AC? Before or after skimming?
 

Travis1

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great read, thanks lanzo.
I would say after skimmer, "cleaner" water.....
i will be using an external skimmer, could i use the activated carbon on the oulet of the skimmer? would that be effective enough?
 
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Shot guys.now i must start singin a song. Mechanical 1st, chemical last,Mechanical 1st, chemical last. Memory's like a gold fish
 

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