Carbon in the aquarium

[Fishguy2727]

Carbon use in the aquarium seems to be misunderstood. It seems like almost every book recommends it. Most fishkeepers use it. Every filter has it either built in or available as a separate media. However, it is completely unnecessary for constant use.

Carbon has certain functions in the aquarium. The main one is removing medications. Many medications are very strong and harmful and if not used properly or left in the tank too long can end up causing more harm than good. Because of this it is a good idea to use carbon to remove medications after treatment is complete.

There are a few other benefits of carbon. They are mainly in the removal of odor and discoloration. However, these things should not be an issue at all if enough water changes are being done. At this point it would simply be ‘if it can help, why not use it?’ That is where the other issues come in.

Carbon is not selective. It removes a lot of different chemicals whether they are good or bad. Some of these are trace elements and micronutrients. These are vital for the proper physiological function of fish, plants, and invertebrates. When these nutrients are removed it can lead to many physiological dysfunctions in the organisms. One possible result in some species is Head and Lateral Erosion (HLLE). HLLE may not include erosion of the lateral line. Generally the symptoms are shallow, wide pits on the head, sometimes also on the lateral line. As the condition progresses it can cause the loss of a lot of tissue and can result in the death of the fish.

I believe that many other species have other problems that are simply not as easily observable as HLLE. What we see as a three year old tetra dying of ‘old age’, some recent change in the tank, or simply unknown causes may actually be the result of a physiological dysfunction caused by a poor diet and/or nutrients being removed by carbon. If the carbon removes these nutrients then the fish can’t use them. This can lead to these unseen internal problems. Since almost no fish have necropsies performed there is no way of knowing if this is true or, what I believe is more likely, how bad the problem is. We know from human health that most problems are internal. The fish cannot tell us that anything is wrong and we cannot detect almost any problems until there are obvious external symptoms. This limits us to relatively few problems being detectable.

There have been cases of HLLE where the only change needed was the removal of carbon. In these cases the HLLE developed while carbon was being used. Sometimes other treatments were attempted and either had no effect or did not fully solve the problem. When the carbon was removed the HLLE went away. In some cases the carbon was returned and immediately following the return of the carbon the HLLE returned as well.

As if this wasn’t enough, most carbon is not effective after a certain period of time. The quality of the carbon is a major factor in how long the carbon will be effective. In addition, the amount of chemicals in the water that will be removed will also affect the lifespan of carbon. In general high quality carbon will last from two to four weeks. Most people do not change their carbon frequently enough, so for at least part of the time it is in the filter it is not providing any benefit anyways.

In summary carbon is an unnecessary and even harmful media that does not need to be used in the aquarium except for short-term applications such as removing medications. When choosing a filter pick one with customizable media that do not require you to use carbon. Avoid those that provide hybrid cartridges that include carbon built in to mechanical media. When using customizable filters use more biological media in place of the carbon.

[Fishalicious]

Great Article and great you are mentioning this as I also notice more and more people using it constantly instead of only when needed. I totally agree... I use carbon after meds and when using carbon never ever longer than 2 weeks.

[shockshockshad]

nicely written!

[Incredulous_Ed]

Well done. You should submit it as an article.

[mitcore]

great article, well written, thanks for putting in the effort

[digital3]

I believe it was in reading a couple of your posts (before this one) and some additional research that I learned about how to use my carbon wisely. Thanks!

[!!!]

nice article and thanks for spending ur time to write it

the filters i have are the ones that come with those 10g aquarium kits and a penguin biowheel. both come with carbon pouches to use as the media. if not carbon, what should i use instead?

[snipers_den]

:thumb: thank you for the very nice written and informative article.....:thumb:

[fraggle]

Thanks for that! Found it very helpful. Now understand the carbon contribution to the tank a whole lot more!
Cheers mate!

[A340]

Very good article. However, I do feel that you have missed a few points.

One of the original reasons to use activated carbon in the aquarium (and still one of the main reasons used today) is that activated carbon also helps filter out any impurities such as chlorine, chloramine, coppers and other metals that can find it's way into the tank through water changes and not completely removed by a water conditioner.

The use of carbon has been documented as being a contributing factor in some fish diseases such as HITH, however, only in species prone to HITH such as Oscars.

Also, the use of carbon (especially in planted tanks) is still being debated. For every source claiming that the cons out weigh the pros, there is another source claiming that the pros out weight the cons.

[NickFish]

Very good article thank you.
I use carbon in my aquaclear filters. If I choose not to use the carbon then what should I use instead? The only other thing I can find is ammonia clear stuff. What to use in place of carbon?

[shockshockshad]

Just don't use anything! You don't have to fill it. I only use the sponge and ceramic rings, but I will get some peat pellets to put in there.

[Fishguy2727]

Exactly, use the mechanical and biological.

For those that come with cabron built-in, many people simply save money by buying padding for crib liners at places like Wal-Mart and cutting it to fit the cartridge.

Yes, carbon is evidenced to contribute to HLLE in species that can come down with it. But if it does that much to those species, are we certain there are no internal effects in other species? For something that is unnecessary why risk it?

When things change there is always debate. There will be those who stick with the old, sometimes even in the face of undeniable facts. Others take it all in and try both or just teh new. Carbon does remove trace elements and micronutrients. Those are needed for fish, plants, and invertebrates. Perhaps the best examples are in saltwater in reef tanks where EVERYTHING can be vital. It is generally recommended that carbon, if used, is used for a few hours each month.

In planted tanks those that have done it both ways say that without carbon the plants simply seem to do a little better. So although it won't kill them, since it is not necessary and they should do better without it, why waste the money on it?

Some people treat incoming water with carbon. If you need or want it as a backup for chlorine or heavy metals, this is how it should be done, not used constantly. If this is the case putting high quality carbon in for an hour or so after a water change will achieve what is needed without beiing in all the time which can lead to the problems described. However, most water supplies after being treated with the needed dechlorinator and/or metal detoxifier should be fine for the fish. If you have abnormally high metal levels or something like that then treating the incoming water is fine.

Obviously if you use carbon your fish will not all of a sudden die. I think all of use started off using carbon. Short of the species very susceptible to HLLE there are no major health risks. But again, unnecessary and can be harmful, then why use it?

[Sasquatch]

Once again, a very good article Fishguy.

Another potential danger with carbon (and other similar sequestering media) is that if the water chemistry changes the media can release the products that it has sequestered. This often happens when you add salt as a treatment for certain diseases. The salt ions replace the other ions on the carbon and re-release them back into the aquarium.

[NickFish]

If i didn't use carbon wouldn't the rings move down to the middle of the holder thing? Is this ok or is it supposed to be at the top? Could I put in 2 sponges instead? How often do the sponges need to be replaced?
Good article!

[Sasquatch]

If i didn't use carbon wouldn't the rings move down to the middle of the holder thing? Is this ok or is it supposed to be at the top? Could I put in 2 sponges instead? How often do the sponges need to be replaced?
Good article!

We have a small aquaclear and we set it up with some polywool in the bottom for mechanical filtration and two sponges as a surface for biological filtration. The polywool is effective enough (when changed regularly) that we haven't changed one of the sponges in months.

You could do the same with ceramic rings, just put them in a nylon bag, like one you emptied the carbon out off ... :hmm3grin2orange:. I think that they also sell empty bags designed to fit in AC filters, or you could just use nylon pantyhose.

[Fishguy2727]

Yes, just fill it up with more biological media.

[NickFish]

Yes, just fill it up with more biological media.
Such as?
What would you recommend?

[kkevvy]

Such as?
What would you recommend?

I'd just add some more of those ceramic rings. Theres other stuff out there as well. Open-cell foam works nicely.

[Fishguy2727]

For my AquaClear and Fluvals I just add more of their biological media, Biomax.

[Ellen4God]

Megan also suggested that you could just cut a small hole in the bottom of a carbon cartridge and just shake all of the carbon out, and then use the empty cartridge. That's what I did.

[A340]

When things change there is always debate. There will be those who stick with the old, sometimes even in the face of undeniable facts.
Agreed 100%, there will always be a debate. There are the "stubborn old schoolers" and the "young rebellious", dead set on new is better. Yet, there is, as of yet, no hard evidence that neither constant use of carbon or not using carbon is the best way to go.

Obviously if you use carbon your fish will not all of a sudden die. I think all of use started off using carbon. Short of the species very susceptible to HLLE there are no major health risks. But again, unnecessary and can be harmful, then why use it?
Why, if there is no hard evidence against the use of carbon in an average community tank, and one has been using it for years with no ill effects, why call it useless and not use it?

I'm not disagreeing completely with you. You have some very informed and valid points, but I do believe, until there the debate is clearly won, the constant use of carbon can have beneficial purposes.

[NickFish]

Ya there will always be a debate until somebody definelty for sure proves or disproves either side.
How often do you change your biomax?

[Tooch]

I'm not saying one way is right over the other, just my $.02. I've always used carbon in all my tanks. It's in my feeder, my daughter's 10gal, my 40gal Piranha tank, and my 150gal. The fish are all healthy and happy. Until I see something wrong with them, I'm going to keep using it. I'm kinda following the "If it's not broke, why fix it" idea. I did take the carbon out while medicating my paroon for a big scratch he has, but I'm adding it back in today. As soon as I took out the carbon, it seems like my water got cloudy. I do a ~30% water change every week. Over the course of medicating him, I've been doing 10% changes daily to try to help the cloudiness. I'm hoping putting the carbon back in will clear that up. I'll update you guys on my findings!

[Fishguy2727]

Outisde of removing meds the only real benefits of carbon are a reduciton of odor and discoloration (the yellowish discoloration of an undermaintained tank). These will not be an issue if you are doing enough water changes.

I believe that if it can cause such bad external effects in some fish (such as HLLE in many cichlids) then there is no way that is the only harm it can do. I do believe that carbon use is simply taking out too much of the good things.

Part of the problem is how we judge success. For example, if the fish lives for four years, then it was fine. Then it dies. We assume that since we had been feeding the same thing, using the same filter, etc. that all of that was fine and not the cause. But that doesn't mean they weren't to blame. Just because something doesn't kill them outright doesn't mean it is not the only thing to blame. People smoke for decades before they get sick from it. Does that mean smoking is okay? No, of course not. I am not saying carbon is equivalent to smoking, but you get the idea. It can be very bad but still not have effects for a long time. When you combine carbon use with a lower quality food, lower water quality, etc. you are making problems for yourself a couple years from now.

I simply see no gain in spending money on an unnecessary and harmful or at least potentially harmful media.

[hpt84]

I think companies sell carbon with their filter not because they know it help the fish for sure, but because they can some extra cents to the price of their filter. I personal use carbon constantly because my driftwood give out tanin acid (i believe that is the name).

[NickFish]

I'm gonna try one of my tanks without carbon and see if there is any change in water quality or the fish over the course of 2 months. See what happens.

[Fishguy2727]

I would try it on one of the planted tanks. Many planted and reef people are supplementing/fertilizing more in carbon tanks because of the reasons discussed.

[mitcore]

i use carbon in 3 of my 6 tanks, i think that it is good only because it can keep the ammonia and nitrites down, but this is my opinon only

debates a great keeps us all on our toes
LOL

[A340]

Outisde of removing meds the only real benefits of carbon are a reduciton of odor and discoloration (the yellowish discoloration of an undermaintained tank). These will not be an issue if you are doing enough water changes.
And I disagree completely with this. As posted in my original reply, carbon can have more benefits then the ones you stated.

[Fishguy2727]

As stated, if your source of water is so bad that removing heavy metals becomes an issue, carbon can do this. However, I have come across very few people with such low quality tap. Even then it really should be treated before adding it to the tank if it is that bad. The commercial dechlorinators work very well, and many detoxify heavy metals. Based on the risks it can create I do not believe the slight benefit to a very few people means that everyone should use carbon. For those who really need it, yes, use it. But unless you have specific needs for it, I suggest not using it.

[MeganL3985]

I agree about the use of carbon, only for removing meds. As ellen had mentioned, I just cut a slit in my media cartridges and dump out the carbon. There may be a few pieces left inside, but nothing thats going to do any harm or good.