# How do you feel about carbon filtering?



## brewce

After doing a fair amount of reading here and elsewhere there seems to be a split about using activated carbon in filtering a planted fish tank. I have read that it's good for the fish and maybe not so good for plants. I use it for my 65 gallon which is a medium planted tank with about 32 fish and three snails. I change out the carbon once a month. I understand that the carbon can leach back out some of the nasties it has removed once it nears the end of its usefulness. But does it alter or remove ferts for the plants as some claim? In my efforts to have a happy and healthy planted fish tank, I use the carbon. Both fish and plants are thriving. But am I headed for trouble later with the carbon filtering? Where do you stand on this issue ? I really would like to hear from this fine bunch at APC.

Brewce


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## cs_gardener

When I was first starting with planted tanks I always used carbon and changed it regularly. After reading about NPT's with their soil substrates and lower maintenance I moved more in that direction and only used carbon occasionally when needed for a specific reason. It's been about 6 months now since I've used it in any of my tanks and everything is going fine. 

I think it can help when starting a tank by pulling out the nasties during the time when the plants are adjusting to new conditions. I've also used it when driftwood or soil was giving off more tannins than I liked the looks of and also when I needed to remove a medication from the water. For day to day use, I don't really see a need for it anymore.


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## megasycophant

Frankly, I think the use of carbon in general is 'snake oil', except when one has a specific need like removing medications from the water. I'm not saying it doesn't work, just that the quantities present and the change frequencies recommended for filter cartridges, etc, doesn't really result in enough carbon being used or changed frequently enough to make a difference. Just a money-maker.

Then there's the issue of cheap carbons leeching phosphate...

I don't use carbon in fish-only tanks either (except rarely in removing medications).


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## DirtyBlackSocks

It helps if you want to clear up the water, but generally that's a problem with a source that needs to be fixed.

In my opinion, carbon is just something used to cover up problems that have another solution.

It's useful in removing medications, that's about it. Just going to burn a hole in your pocket using it every day...


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## hoppycalif

There is nothing wrong with activated carbon as a biological media. You can use it when you start up a tank, to absorb some of the excess ammonia, then leave it in the filter to act as a biological media.


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## megasycophant

Straight activated carbon (unless you're talking AmmoCarb or some sort of specifically impregnated carbon) does not bond to ammonia. It probably generally doesn't hurt, but I don't leave it in myself because it can leach back into the water column whatever it's soaked up. It may have a high surface area, but I think we've generally got plenty of that, unless you've got no plants (including algae) and a very high stocking level.



hoppycalif said:


> There is nothing wrong with activated carbon as a biological media. You can use it when you start up a tank, to absorb some of the excess ammonia, then leave it in the filter to act as a biological media.


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## Andi

I'm confused. If leaving carbon in is a concern that things will leach back into the tank, well, if the carbon wasn't used, wouldn't those things still be in the water anyway?


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## imeridian

That's pretty much the point. If you're not going to use the large quantity required and change it regularly, you're basically just throwing the money for the GAC away. A simple water change would be a much more effective method instead.


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## Zippin

Well if carbon is not a good thing in being used all the time, then how about using polyseter pads instead ? I use them and do a water change about 8 - 12 days.


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## brewce

Well as far as this carbon question and planted tanks goes I think the answer is use it for a specific purpose. If you use ferts the carbon will gobble up most of them before your plants really get to use them. Here is a quote on the purpose of activated carbon filtering. 

"Activated carbon removes organic pollutants, some of which discolor the water with a yellowish tint, organic acids, proteins, hormones, antibiotic compounds, and organic compounds as well as a variety of chemicals, medications, metals, and minerals.

Inorganic substances removed are, chlorine, chloramine, colors and odor causing substances such as phenols.

Removed organic, particles and substances adsorbed by the carbon will remain biologically active. Trapped waste particles will still decay and remain part of the aquatic system. Activated carbon is therefore best used on a short term basis and replaced regularly.

The quantity of carbon needed for an aquarium is about 3 tablespoons of carbon for each 50 Gallons of water. Carbon is quickly used up and can be removed after just 24-48 hours. If left in the system longer, it will no longer serve its purpose.

Once the activated carbon has been used up the re-release of the adsorbed substances back into the aquarium is minimal.

Activated carbon will not remove trace elements and is safe to use in reef systems. The uptake of substances like iron, manganese, molybdenum, cadmium, zinc, and carbon dioxide are extremely limited and is insignificant if used only occasionally.

Carbon in planted aquariums should be limited, because many fertilizers contain minerals in cheleated form. These cheleates will be adsorbed by the carbon as organics."

That helped me and I hope others as well.


Zippin, I think polishing your water with floss is good. Makes for cleaner water and better light penetration for your plants.

Thanks to all for chiming in. I am now moving in the direction of less carbon use.


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## brewce

here is the link for the quote in my last message. I had meant to post it before.

http://ph.answers.yahoo.com/question/index?qid=20080129142627AANXj0e


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