Who uses activated carbon?

[Nandopsis]

I just finished reading a artical in TFH about Activated Carbon.

I personaly don't use it, but after reading it i might go back to useing it again. As alot of THF stuff it is perdy much well known facts, but there were a few good points i never knew about before.

A fairly interesting read over all.

Eitherway i want to see who uses the stuff and who doesn't.

[Mighty Prawn]

I have it in all my tanks, but mostly just because it came with my filters. I don't medicate, so I don't ever take it out. Honestly, I asked a few times if it's worth it, and just got hums and haws. I figured if people aren't like, "OMG take it out!!!" it's not hurting anything.

-Hideo

[Toirtis]

I use it for removing the occasional med or contaminant...perhaps 3-4 times yearly...but I make sure to always have the stuff on hand, cause you never know.

[Froggie]

I have it in all my tanks, but mostly just because it came with my filters. I don't medicate, so I don't ever take it out. Honestly, I asked a few times if it's worth it, and just got hums and haws. I figured if people aren't like, "OMG take it out!!!" it's not hurting anything.

Carbon will begin to release contaminates back into the water column after a period of use and must be discarded. The subsequent build up can certainly have some negative effects.

To answer the poll, I do keep some on hand but use it solely to remove medication from the water following a treatment. I think it’s unnecessary otherwise and only costs money.

[Mighty Prawn]

I have it in all my tanks, but mostly just because it came with my filters. I don't medicate, so I don't ever take it out. Honestly, I asked a few times if it's worth it, and just got hums and haws. I figured if people aren't like, "OMG take it out!!!" it's not hurting anything.

Carbon will begin to release contaminates back into the water column after a period of use and must be discarded. The subsequent build up can certainly have some negative effects.

So since I never use medication, should I just discard it completely? I honestly don't know, like I said, everything I read online is very vague and wishy washy.

-Hideo

[Vallisneria]

I only use it for clearing the tank of meds and such. I keep a box on hand but have never really use it.

[Froggie]

So since I never use medication, should I just discard it completely? I honestly don't know

I would discard what you have in the tank currently and either get in a schedule of replacing your carbon every 2-3 weeks or simply quit using it regularly. If you're looking for specific information, I’m sure there are studies regarding activated charcoal, and its absorbent abilities in regard to organic material, which detail the period over which it begins to leech things back.

[TheGr8Blade]

I was reading this elsewhere, that most people don't use it. So if not using carbon what do you use as filter media? Just curious...

[RD.]

Activated carbon works via adsorption, and when used for removing meds etc it's typically done all it can do within 24-48 hrs, and should then be removed. For removing DOC's etc on a regular basis, the carbon is typically spent within 10-15 days, which means it needs to be replaced 2-3 times per month, which adds up over time. Yes, activated carbon does help keep your water clearer, and cuts down on the amount of DOC's in your water, but this can easily be accomplished via weekly water changes.

My AC 500's are set up with one large sponge, 2 blue/white filter pads sandwiched together, then 2 layers of fine polyester media to catch the finer particulates, and then topped off with a bag of bio-max rings. With the exception of the polyester media, the media in my filters lasts for years, and is simply rinsed out once per month.

[Earthgirl]

I have an overflow system, so there is no need.

I had it once in the tank, justto help kick start my mother in law's tank. She also used some bio-balls and some other chemical stuff (can't remeber which ones) and never lost a fish.

In all my tanks before had carbon, but as ever one else said, you must keep on top of it or it will leach harmful stuff back into the water.

[Nandopsis]

The article actualy explains that carbon will leach back into the aquarium after the absorbtion limit of the Carbon has been reached, but it will only leach out as much of the contaminated as it is taking in.

Also one gram of carbon has the same amount of surface area as a football field *according to TFH*...once it gets seeded with bacteria, the bacteria will be eating up some of the contaminates as well.

Mark LeChevallier says when taking that into account "a Activated Carbon Filter can function for prolonged times, sometimes years, depending on the particular circumstances."

Like i said a interesting read.

If you don't have a copy of TFH yet pick it up. The last couple of months have been fairly good compared to the usual editions.

[pat]

Is there a shelf live for activated carbon?

Wouldn't it absorp whatever is in the air and render it useless over time?

[Nandopsis]

Yep... it's like baking soda in that way, but i don't know the shelf-life.

Years ago when i used it, I kept it in a zip lock bag to help perserve it.

[TheGr8Blade]

Learned alot about carbon in this post. Thanks so much for that!

[RD.]

The article actualy explains that carbon will leach back into the aquarium after the absorbtion limit of the Carbon has been reached, but it will only leach out as much of the contaminated as it is taking in.

Not to nit pick, but AC works via adsorption, not absorption. (meaning it clings to the surface of the carbon) The risk one takes with leaving it in for prolonged periods is that certain contaminants, such as heavy metals, can & will be adsorbed by the AC, but can also be knocked off by DOC's. (dissolved organic compounds) While most heavy metals are fairly harmless in the ppb range, when combined & released in large numbers, they have the potential to cause some serious stress on your fish.

http://www.osti.gov/energycitations/produc...osti_id=6876269

"Desorption of heavy metals from the surface of activated carbon was very rapid and indicated no evidence of sorption irreversibility."

http://www.carbochem.com/activatedcarbon101.html

"The intrinsic properties of the activated carbon are dependent on the raw material source. The activated carbon surface is non-polar which results in an affinity for non-polar adsorbates such as organics."

Not to mention that there are many types of activated carbon sold for aquarium use, high heat, low heat, as well as numerous raw materials used to make activated carbon, some far lower in quality than others. Just like most things in life, you get what you pay for.

Also one gram of carbon has the same amount of surface area as a football field *according to TFH*...once it gets seeded with bacteria, the bacteria will be eating up some of the contaminates as well.

The same thing could be said about many types of media, most of which will not pose the same risk of adsorbing large quantities of harmful substances such as heavy metals.

Mark LeChevallier says when taking that into account "a Activated Carbon Filter can function for prolonged times, sometimes years, depending on the particular circumstances."

True enough, but it makes absolutely no sense to use something that given the right set of circumstances can release a sudden burst of harmful substances, when there is media available that will harbor just as much good bacteria (or more) with none of the associated risks of using activated carbon.

A good growth of bio-film in ones tank (such as algae) will remove the risk of heavy metals in the ppb range, but nothing short of a major water change, or fresh carbon will help you if those numbers suddenly spike due to a sudden release of those heavy metal molecules if/when they are released by the adsorption of dissolved organic compounds.

BTW - if the quotes above were made by Dr. Mark LeChevallier from the American Water Works Service Co., I'd love for him to inform the TFH readers as to how often a municipal water company that uses activated carbon in their systems, changes their carbon out. Also, while his credentials are very impressive, unless I'm mistaken his area of expertise is not with fish, or fish keeping.