# Does the charcoal in my filter take the fertiliser out of the water?



## ukapstt77

Hey guys

Does the charcoal in my filter take the fertiliser out of the water?
I've bought some TNC COMPLETE,  TNC ROOT TABS and some TNC CARBON to dose my tank with.

Thx for the help


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## ceg4048

A small amount.

So what?

Just add more and carry on. Carbon does 1000X more good things than bad.

Cheers,


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## Sacha

Clive, 

I'm intrigued in this last post. What are the benefits of having activated carbon in your filter?


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## ceg4048

Hi Sacha,
  Activated carbon helps to remove discoloration and other organic/inorganic toxins so it's benefits can be worth more than whatever trouble it causes. On the other hand, activated carbon is not a necessity either so if you remove it it not really a big deal. In other words, activated carbon won't make or break your tank so there is really no need to fret about it one way or the other.

Here in JamesC's post is a summary of the bad things that a fresh set of activated carbon removes from the water column:
Does carbon remove trace elements? | UK Aquatic Plant Society

Look in the paragraph labeled High to very good adsorption. Do you see any nasties in that group?. Just about all of them right? Well, those are the things that activated carbon is really good at removing.

Then there is the fact that activated carbon has some of the highest surface area per unit mass - even higher than the atrociously high priced filter media. Therefore it attracts and build nitrifying bacterial colonies in exactly the same way as any other filter media. So even though there is an end to the chemical adsorption after a while, the carbon then behaves as a high surface area biomedia. It never needs to be replaced unless you want to continue to use the adsorption feature.

Activation of carbon is accomplished using high temperature steam often in excess of 1000 deg.C or with other gasses such as CO2 or Oxygen, which essentially bores out tiny holes within the charcoal structure. This greatly increases the number of adsorption sites per unit volume. Charcoal activated in this manner will have anywhere from 500-1500 square meters per gram of material of adsorption area. Activation can also be accomplished using chemical means, such as with strong acids.

You can even use the bio-media feature as a substrate. Carbon works fine as a substrate, although it is a bit light and it may not look good. You can mix it in with other materials to bulk it up and the carbon will develop bacterial colonies there like any other sediment.

When starting up a tank a really good thing to use is a combination of carbon and zeolite, which is a mineral that has a strong attraction to ammonia and that will help control ammonia an other toxic compounds in the sediment.

I mean, there are no bad reasons for using activated carbon. All of these supposedly bad reasons boil down to the fact that a minor amount of Iron is pulled from the water column. Carbon haters always talk about that, but as I mentioned, you can just add more Fe and get on with it.

Cheers,


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## Sacha

Great explanation! Thanks so much. You truly are a fountain of knowledge sir.


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## harryH

Living and learning all the time. The 'old school' method taught us that carbon, once saturated would start to leach toxins back to the tank.
Could this again be the manufacturers lining their pockets?

Because of the fear of this 'leaching' I have always been a bit shy when it came to using Carbon in the filter.
Now Clive has blown that theory out of the water (literally) as it seems from what he says, using carbon is harmless, even beneficial to the nitrifying process?.


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## ceg4048

Well it's another fantasy about leaching. There is no chemical or physical reason for the carbon to drop it's payload of adsorbed toxins. In fact, any of the resins that folks use, such as Purigen, HMA and so forth, work exactly the same. It's just that they target different molecules and vendors tailor the resin compound according to the attraction properties of the resin. At some point the binding sites get filled and any bacteria in the vicinity and that can use the chemicals, such as NH4 just uses what's in their neighborhood.

Again, if the water supply has a continual problem with toxins, then you'll need to add more fresh carbon because the binding sites will become filled. Some people use Carbon filters at various stages in their water purification schemes prior to putting the water into the tank. So for example, there are some RO filter membranes that are easily damaged by chlorinated water. So, that particular RO unit will need to have a Carbon stage before it reaches the RO membrane, and the user has to ensure that the Carbon filter is replaced regularly. So in that sense, yes, regular replacement of Carbon is necessary to protect the membrane.

People get confused and they take certain things as gospel and apply it to every situation. When you understand what is physically happening and the reasons, then you can take the proper actions within the context of each situation.

Bacteria really do not care where they live and carbon has no effect against bacteria. It's strictly an electrochemical interaction between charged particles in the water on the surface of the material.

Cheers,


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## Cherry

On the subject of carbon in your filter - I was told somewhere that it will remove the iron and other trace metals out of the tank- so when I installed my new fluval 406 I didnt put the carbon in - just filled th carbon with biofilm and media? should I have some in?
Thank you x


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## foxfish

As is explained in detail above... it is up to you.... you don't have to use it but use it if you want......


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## parotet

Just a newbie question... I suppose that any charcoal can be used, isn't it? I mean, Does the charcoal from a bonfire has the same properties as any 'super charcoal special for nature aquariums" that cost 20 euros a tiny bag? You mentioned that the ones sold change the colour once they are not active anymore... Maybe this is the difference? Maybe just the promise of having a super planted tank free of algae?


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## ceg4048

No. You cannot just use charcoal from your barbecue pit. The charcoal must be "Activated".

Please re-read my earlier post (paragraph 5 of post #4). Although the properties of coal is pretty much the same, it is the high surface area via activation that allows the charcoal to become much more effective, simply by giving it a capacity to adsorb greater quantities of unwanted molecules. Your barbecue briquettes do not have sufficient surface area to do a proper job. On the other hand, it doesn't have to be purchase from an LFS. Wherever you buy it, you must be sure that it is Activated Carbon.

Cheers,


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## parotet

Thanks Clive... If it doesn't have to be purchased from a LFS where can this product be found? Does it have other common uses?


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## ceg4048

Well, Carbon filtration is used anywhere people need to remove certain toxins from air or water. There are probably lots of different brands of carbon at the big DIY chains because they are especially popular for helping to clean potable water. Any place that sells air filtration equipment will also have Carbon filters. If you can find it in bulk granules that might be better than the blocks, but even the blocks can be smashed up and used. Might find some in garden centers. Best pricing might be at flea-bay or at Amazon.

Cheers,


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## Jafooli

Interesting read, I haven't come across Carbon yet, as my filters don't have it and I've never had a RO unit. I didn't even know charcoal was carbon, dam what was I doing in science. I really wish I paid attention now since entering this hobby, either way its easier to learn as your older.

Anyway funny enough my girlfriend purchased some Charcoal Bamboo shelters, when they arrived to my surprise they were actually charcoal, I presumed they would just be charcoal coloured!! I did some quick research and I did find people mentioning it removes all the bad stuff but then leaches it back, so I now know that's a myth tanks to this topic, so I can presume there shrimp safe?, unless shrimp need FE (Iron), I'm not sure as of yet, I would have to have a look.

This is probably a stupid question but my hands turned black from touching the charcoal shelters obviously as there charcoal , but won't this leak into the water? you also mention above that carbon can be used as a substrate mixed in, would the tank not turn black? I have no idea what I'm on about, but charcoal is messy, not sure if activated carbon is? lol hope that make's sense.


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## three-fingers

Those carbon shrimp shelters and bags of activated carbon are usually covered in dust produced during handling of the products. They should be rinsed under the tap before placing in the tank .


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## ceg4048

Yeah, you really needed to pay attention back in science class mate. Everything that lives on this planet is made primarily of carbon, which is a versatile element. Trees make their food from the Carbon Dioxide in the atmosphere and the structure of their dry matter is Carbon. So when you burn any part of a tree, the residue is mostly Carbon. Millions of years ago trees which had been using CO2 fell in the forest and were later covered with layers of rocks and dirt. The immense pressure from millions of years of debris being piled on top of them turned the Carbon residue in the trees into petroleum. So the petrol in your car has the same origin as charcoal, in this case their particular form is called "Hydrocarbons" and of course, when you burn it in your engine, some of of the effluents are CO2 and CO. That's why these are called "greenhouse gases", because that's how trees and plants get their Carbon.

Because of the adhesive properties of Carbon, it has a very high CEC, so sediments that have inorganic carbon mixed in have a higher CEC than those sediments which are missing inorganic carbon.

Bamboo, like any other plant is made of carbon, so when you burn it the residue will be mostly Carbon plus whatever residual NPK products were in the bamboo at the time. It's not surprising that there are ashes left over. As three-fingers mentions, it's probably a good idea to wash the ashes off before you put it in the water.

Activated carbon comes in a couple of different forms depending on how the coal was processed. You can get loose granular size where the grains are about as big as pea gravel:




You can get them in a less messy package wrapped fabric:




Or you can get the blocks:




Cheers,


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## Cherry

To add to the debate - from a book by Diana Walstad- "Ecology of the planted aquarium"(who was the technical adviser for the for the AGA )
Allepathy 
All aquatic plants contain chemicals that are mildly inhibitory to algae (my note - allepathy happens in the garden too - the chemical helps the plant become dominant in its own space) -this may explain why algae... is unable to take over heavily planted aquaria..
Conversely,some algae secrete allelochemicals that inhibit plants,so of algae growth becomes excessive in the aquarium ,these allelochemicals may inhibit plant growth by water changes and adding charcoal to the filter... In aquariums it would remove almost all allelochemicals, humic substances,artificial chelators,antibiotics and dyes.
..... (However) routine use of activated carbon maybe detrimental,because it removes dissolved organic carbon (DOC) that provides CO2 for plants.However it can be useful in controlling algae or removing yellowish colouring (harmless tannins and humic acids)sometimes generated in new tanks...

So - there you go! so its a yes and no then...


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## harryH

-"this may explain why algae... is unable to take over heavily planted aquaria.."

If only it was so simple as to heavily plant a tank so that algae was 'unable to take over'.


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## Jafooli

I think I've been on this forum to many days straight, Its like a knowledge overload here lol, my head hurts!   Thanks for the information Clive, so the bamboo charcoal is actually bamboo just been burnt at high temperatures.

I guess I now know why my wood turns black when I burn it on my firepit, what have I been doing with my life lol . I'm not going hi-jack the thread, but Its a shame the carbon don't remove hardness,I know hardness ain't important for plants etc, but would love to get it lower so I can achieve breeding more easier.

Thanks again for the information.


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## nickmcmechan

When I set up my fluval edge about a year ago things were going well, then after a few months I kept getting shrimp deaths and couldn't work out the reason why...added carbon to the filter (and have been doing so since) and have a thriving colony....

My tanks seem healthier with carbon than without


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## Cherry

argh - just taken the carbon out of my new shrimp tank - mind you that because its a new tank , the inbuilt filter (trickle) is rubbish - as soon as the sponge gets a bit blocked ,it throws all the water over the side - so had to quickly make ahome made filter to stop it happening - all I have read though indicates that carbon helps with shrimp ......
now if anyone has any ideas how to get it into my nano tank .....[DOUBLEPOST=1396867829][/DOUBLEPOST]yea I have read that carbon is good wiith shrimps as they are so sensitive to copper etc - I dont bother so much with my lage tank - though may bung some in after reading some of the posts on here!

grrr - had to take the carbon out of my new shrimp tank as the trickle filter decides to empty the tank onto to the floor is the filters are the slightest bit blocked ,so had to cobble together a homemade filter as it has only just matured! Now just have to think how to get the carbon back into the filer without that happening (it wasn't the carbon that blocked it , but as the filter pads are ready made complete with a fine polisher - it was that that blocked - and when I tore that off the carbon came out too!!! grrr)..
so any ideas would be appreciated!!!!


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## dw1305

Hi all, 





Cherry said:


> the inbuilt filter (trickle) is rubbish....so any ideas would be appreciated!!!!


 Put a sponge on the intake (The "Fluval Edge" one should fit, it is "RC Hagen A1387 Fluval Edge Pre-Filter Sponge"), and then put a layer of ceramic rings in the over-tank trickle box, that way you will never get a flood, and the problem is solved.

cheers Darrel


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## harryH

dw1305 said:


> that way you will never get a flood, and the problem is solved.



Great idea and you won't get shrimp sucked into the intake too.

Harry


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## Cherry

oh thank you thank you ,was nearly reduced to girly tears !! (and Im far too old for that!!! - and yes no shrimps sucked in either!!!


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