# How to add carbon to be rid of smell



## jimsz (Oct 11, 2011)

I have a 40 gallon tank, responsibly stocked (not overstocked), running two hang on back filters (one filter for 40+ tank and the other for a 10-20).

There is an increasing smell from the water that began a couple of weeks ago. Part of it may be due to the room being small and sealed quite tight but you can definitely smell the "fish" and it is getting worse.

Water is changed frequently, gravel vacuumed, filter media rinsed in pwc water and all the water parameters are testing fine. Details on tank and fish are below.

I have read that Carbon can help rid a tank of smelling. My hang on back filters do have a "reservoir" area - should I buy a pouch of carbon to be inserted here? Do I add it inside the filter media where the charcoal is?

I need to get rid of the smell!





Feeding is every other day, Partial water changes are performed at a minimum every few days and at maximum every day or two. The minimum water change is 25%. In a weeks time 50% - 100% of water is changed. Treated with prime, heated to correct temp. Water is tested every 2 or 3 days and other than a slight increase in Nitrates (.5 from 0) everything reads fine (API liquid test kit). Fish are 5 danios, 10 neon tetras, 3 Platys, 5 ghost catfish, 3 mollys with fat bellies (don't remember the name). Plastic plants except for 3 stalks of Wisperia. Airwand. No algae and the water before a change is very clear with no discoloration.


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## jrman83 (Jul 9, 2010)

If you have room in your HOB, I would put one of the pouches in there if it were me. You can take one of the pouches and just throw it in your tank, but don't think I'd like that much.


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## susankat (Nov 15, 2008)

You say you have charcoal in the filter. That is the same as the carbon. It depletes after 2 weeks and needs to be replaced. If not replaced after a certain length of time it will leach nasties back into the tank which I imagine is causing the smell.


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## beaslbob (May 29, 2009)

Add more plants and stop adding prime. Prime stinks!!!!!!!!


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## jimsz (Oct 11, 2011)

beaslbob said:


> Add more plants and stop adding prime. Prime stinks!!!!!!!!



What does Prime have to do with this?

I use Prime to get rid of the chlorine when I do a water change.


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## beaslbob (May 29, 2009)

jimsz said:


> What does Prime have to do with this?
> 
> I use Prime to get rid of the chlorine when I do a water change.


prime is a sulfur that just plain stinks.

It also (as to all dechlorinators/ammonia blocks) reduces oxygen in the tank.

so the use of prime to control ammonia in a tank deficient in aerobic bacteria will result in a stinky tank.

IMHO the best thing to do is to expand the algae present so that ammonia is controlled, carbon dioxide consumed, and oxygen added.

(edit)
Woopsies the algae applies to marine systems. In FW tank the use of live plants actually does much better. (/edit)

But that's just my .02


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## jrman83 (Jul 9, 2010)

Prime has a sulfur smell. Not so much of a fishy smell like you say. You still need a de-chlor if you stop using it.


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## jimsz (Oct 11, 2011)

beaslbob said:


> IMHO the best thing to do is to expand the algae present so that ammonia is controlled, carbon dioxide consumed, and oxygen added.



I have 0 reading for ammonia and have for quite some time. 

I use prime to dechlorinate water when performing PWC.


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## jimsz (Oct 11, 2011)

jrman83 said:


> Prime has a sulfur smell. Not so much of a fishy smell like you say. You still need a de-chlor if you stop using it.


I have no intention of not using Prime. The smell is not from Prime.


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## jrman83 (Jul 9, 2010)

I agree.


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## jimsz (Oct 11, 2011)

Would it make sense to simply remove a lot of the old carbon in the filter media and replace it with the new? The rest of the media would retain the good bacteria since there is no reason to change it.


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## FishFlow (Sep 13, 2011)

I would find a way to put new carbon in the hob without replacing the mechanical/bio filters. (Yes for the short version.  )


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## BBradbury (Apr 22, 2011)

Hello jim...

Chemical filtration (carbon) will absorb tank odors, but frequent and large water changes will do a much better job of keeping the tank clean than carbon can, since water changes remove many more dissolved substances that can cause the foul water smell.

Instead of doing small water changes that add up, do one per week of at least half the tank's volume and maintain the routine. Constantly flushing large amounts of clean, treated water through the tank is the best and fastest means of stabilizing the water conditions.

B


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