Is this true about carbon?

[derek_s]

Directly form Bulk Reef Supplies website:

Carbon can be left in the tank for prolonged periods of time but after a few days it becomes significantly less effective as most of the pores have filled. Carbon is an ideal place for good nitrating bacteria to populate and if left in the tank for prolonged periods of time a good portion of your filtrating bacteria may be populated within the carbon. When the carbon is removed at this point it may take a significant amount of a tanks filtration system with it. If you choose to leave the carbon in the tank for long periods of time only replace half of it at a time to avoid this issue.</em>

 

[george]

Not in a reef. In a system with a canister filter or another type of filter that relies heavily on carbon, I could see that.

 

[ralph atl]

George;214059 wrote: Not in a reef. In a system with a canister filter or another type of filter that relies heavily on carbon, I could see that.

what he said.......anyway, you should change your carbon put every two weeks or so.

 

[derek_s]

How much do you run? BRS said 1 TBSP per 10 gal.

 

[FutureInterest]

There is some data on RC about the effectiveness of GAC for absorption being about 3 days. I think Boomer was the OP. Ouling would just leave the carbon in his sump like a sand bed. It didn't seem to adversely effect his setup.

 

[ralph atl]

corvettecris;214102 wrote: How much do you run? BRS said 1 TBSP per 10 gal.

that sounds about right.

 

[skriz]

yeah, carbon is only effective for a few days to a week. I wouldn't keep it in there longer than that. I used to run it one week on one week off.

 

[ralph atl]

Randy Holmes-Farley
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No, good quality activated carbon brands do not leach enough phosphate to be important. The little DIY test that some folks use is , IMO, just not worth doing. It makes a tiny bit of phosphate look like a large amount.

[B]I am also thinking of running carbon, can anyone elaborate on pros or cons of running 24/7 versus once-in-a-while?[/B]

I personally do not think this is even contentious. I can't think of a con to running 24/7 that I believe to be important. The pro is that you want to remove organics from the tank, and they are present and accumulating 24/7, so you should try to remove them similarly.

There is no evidence that removal of "trace elements" is a negative.

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Randy Holmes-Farley

 

[acroholic]

I have an MRC media container that I fill with carbon (guess about 1.5 liters) and let it run until the flow starts to slow significantly. I have the output slightly above water. When it slows to just more than a trickle, I figure it is time to replace. It usually works out to about every two weeks.

I read that quote about the biofilter on the Bulk Reef Supply site, but I have about 400 lbs of LR , so I seriously doubt 1.5 liters of carbon is going to significantly deplete the biofilter of the tank.
Dave

 

[geno]

This was a very interesting thread -- thanks!

:up:

 

[ralph atl]

Randy Holmes-Farley
<span style="font-size: 11px;">Reef Chemist
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Location: Arlington, Massachusetts
Occupation: Chemist (Drug Discovery at Genzyme)
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I also run it 24/7 and see no reason to not do so.

Running it in a cannister filter is fairly easy to accomplish in most systems. I'd start slow and then ramp up the amount to the recommend dose over time.

In a 180, maybe 1 cup to start, then 2-4 cups at equilibrium. The exact amount doe snot matter all that much as long as you start slowly. Change it after a month or so.

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Randy Holmes-Farley

 

[derek_s]

Good points. I just got in my Carbon from BRS yesterday so now I can change more regularly.

A question for Ralph, since the flowrate through carbon can be slow, and the flowrage through GFO should</em> be slow, and both should be changed every 2 weeks, is there any disadvantage of running them together in a reactor??

I decided to run mine together despite having 2 reactors just because it will be easier to dump it biweekly as a whole as opposed to dumping 2. It runs through the carbon first, then the GFO and they are seperated by a sponge divider. The flow is probably just 5 GPH or so.

 

[ralph atl]

corvettecris;214212 wrote: Good points. I just got in my Carbon from BRS yesterday so now I can change more regularly.

A question for Ralph, since the flowrate through carbon can be slow, and the flowrage through GFO should</em> be slow, and both should be changed every 2 weeks, is there any disadvantage of running them together in a reactor??

I decided to run mine together despite having 2 reactors just because it will be easier to dump it biweekly as a whole as opposed to dumping 2. It runs through the carbon first, then the GFO and they are separated by a sponge divider. The flow is probably just 5 GPH or so.

do not put them together in the same reactor. you can have 2 reactors and tie in series with the carbon first & the GFO 2nd or split off same pump & have them flow separately.

 

[derek_s]

Not to dispute your answer, but why not??

Am I right that carbon can be just as effective at a slow flowrate?

Also, is my 5 GPH good for the GFO, or is it too slow/fast?

 

[acroholic]

corvettecris;214212 wrote: Good points. I just got in my Carbon from BRS yesterday so now I can change more regularly.

A question for Ralph, since the flowrate through carbon can be slow, and the flowrage through GFO should</em> be slow, and both should be changed every 2 weeks, is there any disadvantage of running them together in a reactor??

I decided to run mine together despite having 2 reactors just because it will be easier to dump it biweekly as a whole as opposed to dumping 2. It runs through the carbon first, then the GFO and they are seperated by a sponge divider. The flow is probably just 5 GPH or so.

Chris,
GFO is meant to be used in a fluidised state. Carbon is meant as a flow-thru type media. You cannot do both in the same container.
Dave

 

[derek_s]

Woah, you're gonna have to elaborate. Both my containers are similar in build (upflow reactors). So what do i need to do differently between them?

 

[ralph atl]

I have been running this for a few years, so I cannot remember exactly why, and I don't have time to look it up right now. However, they need to go in seoartae reactors.

Also, here is EVERYTHING you ever wanted to know about carbon:


http://www.advancedaquarist.com/pdf/AdvancedAquarist-2008-01.pdf">http://www.advancedaquarist.com/pdf/AdvancedAquarist-2008-01.pdf</a>


[IMG]http://www.advancedaquarist.com/pdf/AdvancedAquarist-2008-02.pdf"><span style="color: #000088;">http://www.advancedaquarist.com/pdf...ist-2008-02.pdf</span></a>

 

[acroholic]

corvettecris;214226 wrote: Woah, you're gonna have to elaborate. Both my containers are similar in build (upflow reactors). So what do i need to do differently between them?

Pack the GFO with enough room for the upward water flow to suspend it in the container, so it is moving in a fluidized state.

Pack your carbon so it takes up all the room in the container. It has no room to move, so it just sits there and the water flows thru it.

In other words, leave some space in the GFO container and don't leave any in your carbon container.
Dave

 

[derek_s]

That makes perfect sense.

BUT, I thought I read on the back of one of my old GFO containers that you dont want it to "tumble" because it will cause it to grind up and pulverize the media. This doesnt occur in a fluidized state? Or is it just negligible?

 

[acroholic]

corvettecris;214235 wrote: That makes perfect sense.

BUT, I thought I read on the back of one of my old GFO containers that you dont want it to "tumble" because it will cause it to grind up and pulverize the media. This doesnt occur in a fluidized state? Or is it just negligible?

Chris,
I THINK this is the rational for using GFO in a fluidised state and using GAC in a flow thru state:

GFO works thru adsorption. Def: (Adsorption is a process that occurs when a gas or liquid http://en.wikipedia.org/wiki/Solute"><span style="color: #0000ff;">solute</span></a> accumulates on the surface of a solid or a liquid (adsorbent), forming a film of molecules or atoms (the [IMG]http://en.wikipedia.org/wiki/Adsorbate"><span style="color: #0000ff;">adsorbate</span></a>).)

GAC works thru absorption. Def: (It is different from [IMG]http://en.wikipedia.org/wiki/Absorption_(chemistry)"><span style="color: #0000ff;">absorption</span></a>, in which a substance diffuses into a liquid or solid to form a solution.)

In other words: GFO adsorbs phosphate and binds it on it's surface, so you want as much contact between the surface area and the water as possible, thus a fluidised (tumbling) state is the best to maximize surface contact with the water.

GAC absorbs into it's pore structure (inside the GAC), and this is best accomplished with water being forced thru the media while it is still.

It is counterintuitive, but I was told by a bulk GFO supplier that there is more breakup in the pelletized GFO that the granular GFO in a fluidised state.

You can use GFO in a filter bag or even in a non-fluidised state (packed like carbon), but it is not as efficient in removing phosphates because it has much less flow thru and surface contact area with the water than in a fluidised state.

I guess which way you use it depends on your needs, but the fluidised state with GFO is the most efficient, I believe.
Dave