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What exactly does filtering through carbon do for the aquarium?

Thanks,
Paulette

Carbon is used in your tank similarly to how it's used in a water filter that you use for drinking water. It's able to trap small particles that cause funny tastes and smells. It's also great (in reguards to your tank) for removing medications.

There is great debate as to if it should be used continually or only in special circumstances (ie: following medications). People with live plants that are adding ferts generally do not use carbon continuously as it also removes ferts that are being added for the plants.

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An excellent question, Paulette...

As an example, here's a list of various items that may, or may not, be present in your tank water that activated carbon will absorb:

High to Very Good:

Antimony
Arsenic
Bismuth
Bleach
Chloramines
Chlorine
Chromium
Dyes
Gold
Hydrogen Peroxide
Odors
Pesticides
Phenols
Tin
Trihalomethanes.

Keep in mind we're talking "trace" elements here.

Some other chems are slightly reduced by activated carbon as well.

Some plant lovers are concerned about nutrients being removed by activated carbon. The essential, at least a couple like iron and nitrates, are not absorbed by activated carbon.

--garyroland.

Last edited by garyroland at 19-Nov-2004 09:53

Hi,
Without getting too technicial, filtration with activated
charcoal (carbon) removes organic molecules, such as fish
urea, or elements such as Copper (Cu) from the water.

Because of this, users are instructed to remove the carbon
from their filters when medicating their tanks. Conversely
they put carbon back into the filter at the end of the
treatment period to remove the medication.

Activated carbon will only "soak up" just so much organics
and elements such as Copper (Cu), and then over time it will
loose that capacity, from then on it becomes just
another part of the filter system, filtering out the larger
size debris. Depending upon the fish load it should be
changed out on a regular basis (biweekly, monthly, etc).

A long, long, time ago it was made of bone charcoal and
was called activated charcoal. Once it lost its
"activation" you could spread it out on a cookie tray and
bake it in the oven at 450 for a while, and "reactivate"
it. Then, it was almost a necessity for a well filtered
and maintained aquarium. However, with todays filters,
it is nearly completly unnecessary. About the only use
in todays aquariums would be to remove parts of medications
from a tank once the treatment period was over. But, you
could do the same thing with daily or weekly, 10-20% water
changes.

Old habits die hard, and in some cases become "old wives
tales." That, IMO, is the way the use of carbon has gone.
We did not know then what we now know about filtration
and biological filters, the Nitrogen Cycle. Nor did we
have UGFs, Canisters, BioWheels, Fluidized beds, or
plant filters. You don't really need to use carbon all
the time, and instead can stick a sponge in it's place
and have just as good a filter.

Frank


-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

Thanks for the replies.

Frank, I have a question for you. I have a 5-gallon tank with 3 goldfish and 1 golden gourami (long story, that). I know this is way too many fish in the tank, but they are my 5-year-old daughter's fish and so we are stuck with them.

The tank always runs high with nitrites (and thus ammonia). I can't change the water often enough and don't have the time for it, either.

The tank has a Marineland biowheel filter system on it. I use my own carbon and floss in the filter tray (I saved a plastic holder, cut off the used floss, and dumped the used carbon. I refill it as needed with my own carbon and floss. It's much cheaper this way!). I'm thinking about nixing the carbon and putting in zeolite. I currently have a zeolite pillow on top of the floss and it is helping with the ammonia. I figured I could use more zeolite and it would be in contact with more water if I put it in the filter tray instead of carbon. Any thoughts.

Thanks,
Paulette

Paulette, I know you mean well keeping the goldfish, but that's seriously overstocked. Goldfish grow big.

While I'm not trying to lecture as to how to raise kids, it's somewhat (IMO) irresponsible to teach them that goldfish can live in bowls. They are pond fish and require the space of a 55 gallon as a minimum for fancies (like the one pictured above) and 125 for a common (they really don't belong in ponds).
No matter what you do along the lines of filtration you're likely to kill those fish @least 30 years before their time (no not a typo thirty years ).

I know that she might be attached, but do what's best. Explain that just like you cant keep an elephant in a shoe box, you also can't keep a goldfish in a little tank. Then return the goldfish for a beautiful male betta. They do quite well in smaller tanks, don't require filtration, and few people can resist the beautiful fins. Of course if you're lucky enough to be able to have the room for a pond in the backyard....that's also an option :88).

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Okay, but you didn't answer my question about substituting zeolite for carbon. Do you think it would work?

Paulette

Short answer No.

Way to many other factors. With goldfish the biggest issue is how many gph a filter is running. Even with a filtration system to rival the ones in aquariums you'll still end up killing the fish.

I only run bacterial and mechanical filtration on all my tanks, including the one for the goldfish. Using chemicals to do what's easily done by proper stocking and regular maintence isn't really the way to go @this hobby. Considering the size of the tank, I can't really see how water changes are a problem.

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Last edited by Babelfish at 19-Nov-2004 11:38

I have a 5-gallon tank with 3 goldfish and 1 golden gourami (long story, that). I know this is way too many fish in the tank, but they are my 5-year-old daughter's fish and so we are stuck with them.

The tank always runs high with nitrites (and thus ammonia). I can't change the water often enough and don't have the time for it, either.

. . . .


Well, first off, I don't see why these fish being your daughter's means you have to keep them. Despite what most people tend to believe, young children are very smart and are more than capable of understanding that a goldfish (which grows quite large) would be much healthier and happier in a larger tank. What do you think will be easier to explain to your daughter? The fact that her pets will be much happier if given up for adoption to someone else with better means of caring for them, or that her mommy was careless and killed her beloved pets slowly and painfully by ammonia poisoning and stunting? The choice is yours, the only thing I can assure you of is that as young as she is, your daughter is capable of understanding what is best for her pets.

A better option for your 5 gallon tank would be a (one) pretty male betta (siamese fighting fish). With more appropriate inhabitants, it will be much easier for you to stay on top of those water changes. With a betta in there, you'd only need to change out 1/2 to 1/4 of the water weekly. Another option might be to get 2-3 male fancy guppies. Both guppies and bettas are very nice, colourful fish that are great for small children to watch. I'm sure your daughter, like most 5 year olds, would be much happier watching and caring for healthy pet fish than sick ones in dirty water.

Filter media that claims to neutralize ammonia is only a bandaid solution. Those goldfish will die if you keep them in that tank, and your daughter will understand if you take them back to the pet store to exchange for more suitable pets. Be honest with her and set a good example. Care for our fellow living creatures is one of the most valuable lessons we can teach our children, and it's important to start as early as possible.

With better fish in that tank, think about involving your daughter in water changes and tank maintenance, even if that means she's just watching you do it. Fish make excellent pets and learning tools for young kids as long as they are taken care of properly. The choice is really up to you, but I'm sure that if you're completely honest with your daughter about the situation, she will make the right decision as tough as it is.

One way to explain it to her might be to say, "Your goldfish friends are growing up very quickly and would be much happier in a BIG tank where they can grow and live with other big goldfish. It's hard to let them go but if we keep them they will be unhappy and will get sick. We can give them away to somebody else that will be able to make them happiest. What do you think?"

Also explain that you can get smaller fish that will be happy in the tank that you have. I'm sure your daughter will understand what is best for her friends.

On the other hand, if doing 25-50% water changes weekly is too much for you to handle with your schedule, maybe keeping fish is not the best idea. Like any other pet, they do require time and effort devoted to their care.