# activated charcoal in the planted aquarium



## Inga (Jun 8, 2010)

Now I know that activated Charcoal pulls nutrients out of the water that the plants use but I wonder, how long does the effects of the Activated Charcoal last? In a normal HOB filter, the filter pads are not changed out real often, you just rinse them out in the tank water and replace them. The Activated Charcoal can't keep working forever, can it? I am NOT a normal person apparently as I do change my filters a bit more frequently. I am a clean freak and I fight it with fish keeping as I might over do the clean in a tank. I already change 70-75% water every 4-5 days and I change the filters regularly too. ( I won't admit to how often) anyway, how long would you say that the Activated Charcoal lasts? 

If one is dosing the tank with Flourish, how much of that can the charcoal absorb? How long does it last? I purchased 4 boxes of filters so... 16 filters and I am going to stop buying more but I am too cheap to throw them out so... am I damaging the plant growth by using these filters at all? If I change them less frequently would it be alright? How long does the Activated Charcoal last? How much can it pull from the water? Thoughts?


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## 1077 (Apr 16, 2008)

Given the small amount of carbon found in most cartridges, I would say it is exhausted within two weeks. (generous estimate).
Carbon is said to have an affinty for metals, and considering that plant's also need metals such as Iron,magnesium, and perhaps other's that we add in the way of fertilizer's,,it doesn't seem to me to provide a benefit to planted tank.(course it don't last long either) 
Have spoke to other's who claim that carbon doesn't really have such a negative effect on planted tank's but these folks in large part ,,are running high energy tank's with quite a bit of light and CO2 injection which precipitates frequent dosing of all nutrient's.(daily)
Perhaps what little the carbon removes is not that important with these tanks.
I don't use carbon unless I am trying to clear a tank of residual's such as those from medications.


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## AbbeysDad (Mar 28, 2011)

Everything I've read suggests that activated carbon is exhausted in 7-10 days. Because of this, many feel that carbon is a bit of a waste, like throwing money away. 

Although I'd agree that continued use may be unnecessary, I personally have to wonder if the periodic use of carbon may have some benefit in removing unwanted contaminants from the water.


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## Byron (Mar 7, 2009)

Aside from medications, live plants will remove everything that carbon will remove from the water. This includes the bad stuff, but some of these things the plants need, not only the mineral nutrients that 1077 mentioned but perhaps even more importantly DOC (dissolved organic carbon). This is a major building block of life, and as most of us know, with natural planted tanks we want to retain as much carbon as possible.

AD is correct that the activated carbon in filters does become exhausted, though I have not read specific time frames. [I would be interested in following that up if AD could point me somewhere, perhaps?] I have always assumed it depended upon how much stuff the carbon was adsorbing.

Carbon may be beneficial in new tanks at controlling algae. This is because it is removing the DOC's which algae obviously need and with the common instability of the water in new setups algae is quicker at taking the advantage. But with sufficient plants and fast growing ones, even in new tanks this should not be necessary.

So Inga, will the store take them back (presumably they are un-used) on credit? I would not use them if it were me. You're trying to get your tanks back in balance, and removing carbon is not going to help that.;-)

Byron.


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## AbbeysDad (Mar 28, 2011)

Byron, I'm afraid my 7-10 day estimate is more based on hobbyist's consensus agreement rather than scientific fact. If one poses the search on Google, you will find somewhat of an avg. of 7-10 days, although many feel it last up to a month or more.
However, I agree with you - as any absorbant or adsorbant, it is exhausted when it has reached it's capacity which is most likely relative to the condition of the water column. Given this logic, one could conclude that the viable use range could be either very short or very long depending on water quality conditions.


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## Inga (Jun 8, 2010)

Byron said:


> Aside from medications, live plants will remove everything that carbon will remove from the water. This includes the bad stuff, but some of these things the plants need, not only the mineral nutrients that 1077 mentioned but perhaps even more importantly DOC (dissolved organic carbon). This is a major building block of life, and as most of us know, with natural planted tanks we want to retain as much carbon as possible.
> 
> AD is correct that the activated carbon in filters does become exhausted, though I have not read specific time frames. [I would be interested in following that up if AD could point me somewhere, perhaps?] I have always assumed it depended upon how much stuff the carbon was adsorbing.
> 
> ...


Likely not since the fool that I am purchased those when I got the filter. I then got into the sponge filter for a long time and now went back to the HOB filter due to the outbreak and plant matter. I admitted to being cheap, being a clean freak I might as well admit to being an over stocker.   When I bought the filter I bought 5 boxes of filter pads. Before everyone labels me as nuts, I will say, I have run into the problem of not being able to buy changeable items for things in the past. You have a unit but can't get filters to fit it... Yeah well that is my excuse so. I have filters, I will use them up. Maybe I will simply cut the bottom of the filter and allow the charcoal to shake out. I am currently only using 2 in the filter with some loose fitting fiber media which I will go to completely once the pads are gone. This is assuming I still use the HOB filter at all which I might now. 

I too felt like they couldn't last long anyway. In part the reason one uses these at all is to house good bacteria which obviously is still present in these pads. The nice thing about them is how easy they are to pull and toss and with 4 pads in the filter, you can change one a month or week or however often you want and leave the other 3 full of healthy bacteria.


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## Byron (Mar 7, 2009)

AbbeysDad said:


> Byron, I'm afraid my 7-10 day estimate is more based on hobbyist's consensus agreement rather than scientific fact. If one poses the search on Google, you will find somewhat of an avg. of 7-10 days, although many feel it last up to a month or more.
> However, I agree with you - as any absorbant or adsorbant, it is exhausted when it has reached it's capacity which is most likely relative to the condition of the water column. Given this logic, one could conclude that the viable use range could be either very short or very long depending on water quality conditions.


Thanks, that is what I've read, so now we're back on the same page.


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## Byron (Mar 7, 2009)

Inga said:


> Likely not since the fool that I am purchased those when I got the filter. I then got into the sponge filter for a long time and now went back to the HOB filter due to the outbreak and plant matter. I admitted to being cheap, being a clean freak I might as well admit to being an over stocker.   When I bought the filter I bought 5 boxes of filter pads. Before everyone labels me as nuts, I will say, I have run into the problem of not being able to buy changeable items for things in the past. You have a unit but can't get filters to fit it... Yeah well that is my excuse so. I have filters, I will use them up. Maybe I will simply cut the bottom of the filter and allow the charcoal to shake out. I am currently only using 2 in the filter with some loose fitting fiber media which I will go to completely once the pads are gone. This is assuming I still use the HOB filter at all which I might now.
> 
> I too felt like they couldn't last long anyway. In part the reason one uses these at all is to house good bacteria which obviously is still present in these pads. The nice thing about them is how easy they are to pull and toss and with 4 pads in the filter, you can change one a month or week or however often you want and leave the other 3 full of healthy bacteria.


Perhaps you can sell them. A post in our classifieds section...?


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