Carbon or No Carbon?

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whiddett

Aquarium Advice Regular
Joined
Apr 17, 2008
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69
Location
Norwich, England
Hi. I have 2 aquariums made by Juwel which come with the Juwel Filter system and sponges. I am told that it is very important to change the Carbon Sponge in this system every 4-6 weeks. However, I dont actually know what the Carbon sponge does and I have noticed people on this forum often tell people they dont need Carbon. Can anybody advise me on what the Carbon does and when it is or isnt needed? I'm getting concerned as to whether they are a waste of money or not as I have all ready been told that the Nitrate removal sponge is a waste of time and is pointless to replace.
 
I'm kind of shaky on this topic myself, but I will explain it the way I understand it. The carbon is used in a filter to help remove organic waste and any certain impurities in the water. By doing this it helps the water maintain clarity. For example if you have driftwood in a tank that leaches tannins (a harmless chemical that colors your water very light brown) the carbon will remove it for clear water. It is also used to remove medications from the water once the treatment is finished so it is important to remove the carbon if you are treating sick fish with medications
So with the benefit of clear water and organic waste removal why not use it? The answer is two fold. First the carbon - which acts like really small porous sponges - fill up quicker than the rest of the media in the filter. When this happens the carbon (now saturated with impurities) start releasing them back into the water and puts a strain on your biological filtration. The second is that if a tank is set up and established biologically there is no need for the carbon. Nature will do the work and keep everything clean. Some of the larger fish tanks (especially saltwater) have minimal mechanical filtration. They rely on water circulation and nature. But if you are going to use carbon keep this in mind, I would change the carbon half way through the time you normally wait to change the filter. It's more work and you run the chance of disturbing the biologics already established in the filter but it is safer than having the carbon reverse on you. :scrambleup:
 
Warped pretty much nailed it. Unless you have a specific need to run it (removing tannins, meds, etc) there really is no need in running it on a fully established aquarium. Carbon only lasts in water about 1 month, so if you do want to run it it'll need to be replaced monthly.

On the flip side, other than the cost, there is no downside to running it as long as you change it out when it needs it.
 
Hmm. I think I'm even more confused now. I think I should explain a bit more about the filtration system I use. The system comes as standard with all 'Juwel' fish tanks here in Europe. I get the feeling that you guys in the US do things differently. The system has 2 fine blue sponges at the bottom. Then above that is a coarse blue sponge. These sponges have the bio-cultures in them. Juwel say to replace one of these every 3-6 months but I've been told that rinsing them in tank water during a water change is fine. On top of that is a green Nitrate removal sponge which Juwel recommend to replace every 6 weeks. I've been told that these are pretty pointless and that they cant work as the bacteria that feeds on Nitrate requires low oxygen conditions. Then on top of that is the carbon sponge which is recommended to change every 4-6 weeks and then finally at the very top is a poly pad that filters out dirt particals in the water and needs replacing/cleaning every 1-2 weeks.
The following link is to Juwel's website where it briefly describes each sponge and its function JUWEL Aquarium Homepage
Now, I have had my 1st 125litre tank running for over a year now and I am still replacing the carbon every 6 weeks. From what you are saying this is not necessary. But what is it that the Carbon removes? Does it no longer remove anything now the tank is established? If I stopped using Carbon is there anything I could test the water for to make sure that levels are not getting too high? I hope this info allows someone to give me a considered opinion on what I should or shouldnt do.
I also have a new tank that has been running for 11 days and has the same filter system. If I dont need to use carbon, at what point should I stop replacing the carbon sponges?
Thansk
 
Carbon does nothing but polish the water and remove chemicals that are there from medication. Generally it is not necessary. That being said, there is no need to remove it after its expiration as it is good surface area for bacteria to grow. Keep it until it breaks.

Sponges are mechanical filters, straining out big particles from the water, but they are also surface area for bacteria to grow and act as a bio filter. There is no need to replace these unless they are falling apart. Once a month you can rinse them out in old tank water, not tap water as chlorine will kill the bacteria you've built up on it.

When the time comes to replace the sponges, there is no need to go with the specific brand. I just stuff my canister filter full of polyester stuffing. It's available in any craft store and serves the same purpose that a sponge would.
 
there is no need to remove it after its expiration as it is good surface area for bacteria to grow. Keep it until it breaks

You sure about that? From what I hear, leaving carbon after a month can be more trouble than its worth and is likely to release the garbage it collects back into the water.

I've never used carbon myself as I've had no need to. Unless I know for a fact I need it, I don't use it, regardless of what the manufacturer says. I check here first.... If I had a dollar for everytime I was told "you'll need this" and it turned out to be not true.

I understand your confusion. I would use the course and fine filter pads, perhaps some ceramic noodles (beneficial bacteria colonise in them) and that's it. Filters may look different, but they all generally function in similar ways.
 
These sponges have the bio-cultures in them. Juwel say to replace one of these every 3-6 months but I've been told that rinsing them in tank water during a water change is fine.

I agree that you can use filter pads until they fall apart. They last far longer than the manufacturer says. Keep in mind it is in the manufacturers interest for you to keep buying their products. If you want to replace it, only replace 1/2 of the pads at any one time and never replace all of them at once.

If I stopped using Carbon is there anything I could test the water for to make sure that levels are not getting too high?

Carbon removes nothing you can test for. I wouldn't be using it in any tank unless you have a specific need to use it.

Here's a bit more on it.

Activated Carbon for the Aquarium
 
I've been told that these are pretty pointless and that they cant work as the bacteria that feeds on Nitrate requires low oxygen conditions.
There is no bacteria that feeds on Nitrates. The bacteria feeds on Ammonia and Nitrites, turning the Nitrites into Nitrates. If you have live plants in your tank, they feed on the Nitrates, or you need to watch the levels and perform Partial Water Changes (PWCs) regularly to keep them under control.
 
There is no bacteria that feeds on Nitrates. The bacteria feeds on Ammonia and Nitrites, turning the Nitrites into Nitrates. If you have live plants in your tank, they feed on the Nitrates, or you need to watch the levels and perform Partial Water Changes (PWCs) regularly to keep them under control.

You are wrong. There is bacteria that feeds on Nitrates. Or how else do you think water quality is maintained in the wild? Only thing is these bacteria require low oxygen conditions such as beneath a layer of silt and sludge.
 
Plants take care of nitrates. Plants do help out with ammonia and nitrites as well, but water changes and plants are you nitrate removers.
 
Also consider that nature does have some sort of water change, well more of a top off and removed by evaporation.

As for carbon, I'm a newb, my filter had it, I dumped it out after the 1st 2 days. From everything I read from people smarter than I, its recommended to just use to remove medications ect..
 
Thank you agentm.

Nitrates are fertilizer for plants. Algae love it, and that is why PWCs are so important. If you would like more info on the nitrogen cycle, here is an article that explains it more in-depth. There are only 2 bacteria - One for Ammonia, and one for Nitrites. The Nitrates are a bi-product that acts as fertilizer for plants (including algae).
 
There is no bacteria that feeds on Nitrates. ..

Not entirely accurately, though usually the case in pretty much all FW aquarium set-ups (if THAT makes any sense :rolleyes: )

The type of bacteria which CAN process nitrate into harmless nitrogen gas (and thus complete the nitrogen "cycle"), exists only in anaerobic environments. Unfortunately these anaerobic environments can't easily be replicated in most FW aquariums.

Regarding carbon use, is there any solid proof of carbon leaching what it adsorbed back into the system (to the extent where expended carbon proved to be detrimental to the aquarium). I'm not sure if it is a myth or whether the "leaching" isn't as significant as it is often cited. My understanding is once the carbon has adsorbed all it can, adsorbtion ceases and its role in the aquarium shifts from a chemical media to a biological one.
 
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Anaerobic bacteria does exist and it does remove Nitrates. Here's an article that describes it. This type of bacteria is more commonly discussed in SW aquariums with the use of live sand beds and live rock, but it can exist in FW aquariums as well. Most find it much easier to simply take care of Nitrates through regular water changes (which benefit the aquarium in other ways besides removing Nitrates), which is why it isn't discussed much in reference to FW aquariums.
 
Anaerobic bacteria does exist and it does remove Nitrates. Here's an article that describes it. This type of bacteria is more commonly discussed in SW aquariums with the use of live sand beds and live rock, but it can exist in FW aquariums as well. Most find it much easier to simply take care of Nitrates through regular water changes (which benefit the aquarium in other ways besides removing Nitrates), which is why it isn't discussed much in reference to FW aquariums.


Nice read, I was not aware of any anaerobic organisms. So this specific bateria I take is Aerotolerant? Very interesting topic, learning eveyday
 
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