Weekly Debater: Carbon

[Debater]

This week's debate:

Carbon is commonly used in some people's reef tanks. Is it wise to use carbon? If so, should it be used continuously or periodically? If carbon is used, doesn't that mean you are removing some required trace elements? What are your feelings about carbon?

Remember, this a debate, so don't treat it as a newbie that is trying to get information. State your opinion and, if available, use material that will back up your opinion. Tell others why that you think they are wrong, respectfully, of course.

If you have an idea on a topic that would be good to debate about, please let one of the ops know or email me by hitting the email icon below this post.

Sorry guys for taking so long to post a new debate. I will try to not let it slack again.

 

[leftovers]

I believe that carbon is one of the most underutilized filters for reefs.

It will:

• Neutralize toxins
  Remove tannins and other water yellowing agents
  Filter your water of organics and detritus

As for removal of trace elements I think that is plain bunk. I am of the opinion that we add more trace elements via our processed foods and even water changes, that even running carbon continuously doesn't dent the trace elements found in our tanks.

I consistantly find that tanks that run carbon have clearer water and better over all water quality and better growth and more stable/happier IMO occupants.

 

[Bill2]

I use carbon when I feel like it. Either my water is turning a bit yellow or there is a reason why I think I should (aka Rio disease )

I do think it only helps, but i'm sure someone will state otherwise.

 

[Anonymous]

In my current tank I run carbon all the time. I have lots of softies and stonies and when I run the carbon things seem to stay healthy, when I don't things go down hill. I have always done monthly, at least, water changes (with and without carbon) and I think this replaces what ever benificial trace elements the carbon may remove.

RR

 

[randy holmes-farley]

leftovers:

As for removal of trace elements I think that is plain bunk. I am of the opinion that we add more trace elements via our processed foods and even water changes, that even running carbon continuously doesn't dent the trace elements found in our tanks.

While I agree with that assertion, I think that in some cases, impurities coming from calcium and alkalinity addition greatly swamps even those from food. Simon Huntington recently showed that copper from his CaCO3/CO2 reactor was about 10x from the food that he uses.

 

[wombat1]

I run about one cup of GAC in a 30 gal at all times, and change it biweekly. Regular small water changes will replace trace elements in the right quantities. I only dose with Kalk for all evaporation and I change a gallon a week. Has anyone ever tested skimmate for the concentration of elements to see how much they remove???

 

[Anonymous]

I toss a big of Chemi-pure in the sump near the return pump. I change it out every 4-6 months. I've never had my water turn yellow at all. It works for me!

Louey

 

[wade1]

While I agree with that assertion, I think that in some cases, impurities coming from calcium and alkalinity addition greatly swamps even those from food. Simon Huntington recently showed that copper from his CaCO3/CO2 reactor was about 10x from the food that he uses.

This just seems to back up the use of carbon as a valid method for removal of waste. As per another long winded debate not long ago, you have shown that many organics bind metals. In that case, carbon and skimming should remove those complexes rather effectively. Esp if we keep up with regular changes so that localized acidification (from bacterial / algal colonization) doesn't shift the balance back to ionized forms. Correct?

I personally use carbon continuously, although certainly not regularly.

From studies done in our department, it is believed that carbon does not act in a purely thermodynamic manner concerning its binding of organics. It appears to be more active, therefore not subject to thermodynamic equilibrium. That is another point in favor of its use... it doesn't have the propensity to accumulate and then come to equlibrium with the tank.

Now, to play devil's advocate.... I also use a small amount of phosphate absorber mixed with the carbon (of course, I buy the cheap kind) to prevent phosphate leaching out of improperly prepared carbon. I think cheaper carbons used regularly will bolster the phosphate levels in a tank leading to algae and cyanobacterial blooms.

Wade

 

[Anonymous]

IMO it's not yay or nay. Carbon is very necessary especially in tanks with softies, I've personally given up trying to keep soft corals and stonies together however if you wish to have any long term success frequent water changes, light stocking, and use of a good carbon are the only way.

The real issue with carbon is quality and for how long.

If you pull up the old GAC tests** you'll see that not all Carbon performs alike and most of the cheaper carbons IMO are simply another way to piss money away in this hobby. Even some of the better brand names aren't that great. One is a pelletized carbon that is completely useless. It really doesn't perform at all because the carbon in pellet form is so tightly packed that it just isn't efficient. Some of the cheaper carbons are an algae disaster waiting to happen, I've seen stunning phosphate levels when testing some that any phosphate remover would be hard pressed to keep up with. (This is a topic for debate as well. Just how effective are the Phosphate Removers on the market??? I've seen some pretty lackluster performance from most of them.)

How long to run carbon is the other issue. There was an article published in SeaScope IIRC (possibly by Frakes?) of a study of the useful life of GAC. It showed that the life of carbon as a chemical filter was approximately 48-72 hours. After that it was essentially useless and not doing anything. So leaving it running for more than 3 days doesn't seem to accomplish much other than you now have a mechanical filter. Based on this information we currently recommend to customers that they use carbon, once or twice a month for about 3 days at a time, and that you can offset the high cost of a good quality carbon because the quality carbons allow you to use less product.

** Granular Activated Carbon, Part I, Granular Activated Carbon, Part II, Richard Harker, Aquarium Frontiers May-June 1998.

 

[newkie]

I use carbon when I feel like it. Either my water is turning a bit yellow or there is a reason why I think I should...

Exactly what I do. Usually I don't run it. But if something aint right or there is a death it gives me a buffer while I prepare for a W/C (I take 2 days to fill and mix 40 gals).

 

[NaH2Ofreak]

I also run carbon full time. I use the kent brand of carbon. Ive also used black diamond and I feel that they both perform about the same. I use about 2 cups in a mesh bag for my 100gal tank. I change it about every 2 weeks or so. This program has worked well for the past 3 years. I feel that the carbon really helps to maintain clear water. Having clear water makes more effective use of your lighting. I also believe that it helps to remove some of the toxins from the soft corals.

The overflow from my tank passes thru the carbon BEFORE it goes thru the skimmer. After just changing the carbon, the skimmer will not skim for about 2-3 days, after which it kicks into skimming. I feel that the carbon is taking care of most of the DOM during those first couple of days. After that, it is just removing color from the water and so forth. Ive never really had a problem with phosphates or algae blooms.

Dennis

 

[Nelliereefster]

Like mentioned before, Carbon adsorbs/absorbs phenols, tanins and some of the leftover vitamins, food stuffs as well as organics from fish/corals/food additions.

Most studies say that carbon will take out goods as well as bads. The simple solution is water changes to replace the nebulous and unquantifiable "trace element" depletion.

In order to strike a balance, carbon should be used periodically. One week per month, in the middle between water changes should be about right. Also, quantity of carbon to water volume is a sketchy question. For your average 100 gal system, you have a true water volume arounf 80-85 gallons. As a thumbnail, a single bag of chemi-pure will suffice.

ALWAYS perform a phosphate test on the carbon you intend to use. Some GAC was activated with phosphoric acid!!!

Overall, conservative carbon usage is a sound maintenance practice, where the goods far outweight the bads.

 

[Anonymous]

FWIW, I usually don't run carbon and have a steady ORP reading of 260 +/- 10. I've been running carbon and Phosguard now for going on 72HRS and the reading as of yesterday has been at 320 +/- 10. I'm now running the water through a Magnum canister as opposed to dropping a bag in the sump.

My water has never been so clear as seen looking through the sides with the lights off.

Great thread!,
po

 

[Anonymous]

i think carbon should be run regularly, but intermittently-about 3-5 days/mo.

more than a week, and imho-it becomes a bio filter that adds to NO3 production,also loses efficiency from 'pore blockage'.

the argument of not using it because of trace element absorption is also a poor one, imho-all filtration-skimming, and biological, also removes trace elements.so does all livestock :wink:

it seems to do a fine job when used intermittently.