Carbon - What exactly does it Take Out of the Water? (Both Good and Bad)

[that Reef Guy]

I read a lot of Mixed Feelings on using Carbon in the Reef Tank.

Some people Love to use Carbon.

Others are Very Very Fearful of it and say to Never Use it.

Others say to only use it in Emergency Situations.

What I do know is that it Takes Bad Things out of the Water, but it also Takes out Good Things in the Water too.

I hear that saying a lot.

What I never hear is what exactly does it take out?

So that is my question - What Exactly does Carbon Take out of the Water? (Please tell me Both the Bad Things as well as the Good Things).

 

[SantaMonica]

It removes dissolved organics like amino acids, vitamin c, medications, poisons, and colors.

It does not remove ammonia, nitrite, nitrate, or phosphate.

 

[that Reef Guy]

It removes dissolved organics like amino acids, vitamin c, medications, poisons, and colors.

It does not remove ammonia, nitrite, nitrate, or phosphate.

What do you mean by it removes "Colors"?

 

[mwbeach]

Following. Curious as well

 

[mike007]

It removes yellowing from the water. Makes the water crystal clear.

 

[leptang]

I wouldn't say it takes anything out, but the carbon binds with other substances changing the structures of molecules. Far as i know, nothing more.

 

[Squamosa]

It also removes chelated copper, mercury and iron (in the ferric state).

Please excuse the low resolution of the attached table.

 

[Daniel@R2R]

What a great question! Bump for continued discussion by the morning crew!

 

[Randy Holmes-Farley]

In seawater, activated carbon will tend to remove anything that is hydrophobic, or has a hydrophobic portion, or attaches to hydrophobic surfaces.

This is different than freshwater, so you can't always rely on claims measured in fresh water. The reason is that a massive amount of sodium and chloride competes with the much lower amounts of others things that may bind to oppositely charged sites. Acetic acid (vinegar) is an example, IMO. I see it on the list (although I do not know if that is a fresh water list), but I doubt very much stays bound to GAC in a normal reef aquarium.

In general the list of things bound mostly is organics and whole bacteria that may like to grow on it.

The organics themselves may contain other things, like metals (e.g., copper). Copper is nearly 100% chelated (bound by organics) in natural seawater and I expect it is in reef aquaria as well.

Not all organics will bind, but a great many that are colored in seawater will bind, hence the ability of GAC to reduce yellowing of aquaria.

Some amino acids will bind, and some not.

I'd also note that some of the things on the posted list above actually are broken apart by GAC, not just bound to it. Chloramine, for example, releasing ammonia. Hydrogen peroxide, permanganate, ozone.

FWIW, I use GAC 24/7. I use ROX GAC from BRS (wow, a lot of acronyms in a single sentence) :lol:

 

[that Reef Guy]

In seawater, activated carbon will tend to remove anything that is hydrophobic, or has a hydrophobic portion, or attaches to hydrophobic surfaces.

This is different than freshwater, so you can't always rely on claims measured in fresh water. The reason is that a massive amount of sodium and chloride competes with the much lower amounts of others things that may bind to oppositely charged sites. Acetic acid (vinegar) is an example, IMO. I see it on the list (although I do not know if that is a fresh water list), but I doubt very much stays bound to GAC in a normal reef aquarium.

In general the list of things bound mostly is organics and whole bacteria that may like to grow on it.

The organics themselves may contain other things, like metals (e.g., copper). Copper is nearly 100% chelated (bound by organics) in natural seawater and I expect it is in reef aquaria as well.

Not all organics will bind, but a great many that are colored in seawater will bind, hence the ability of GAC to reduce yellowing of aquaria.

Some amino acids will bind, and some not.

I'd also note that some of the things on the posted list above actually are broken apart by GAC, not just bound to it. Chloramine, for example, releasing ammonia. Hydrogen peroxide, permanganate, ozone.

FWIW, I use GAC 24/7. I use ROX GAC from BRS (wow, a lot of acronyms in a single sentence) :lol:

Randy, I am glad you posted.

I know you are considered the Guru of Chemistry.

I was wondering what are your thoughts about the two most common negative things I hear about Carbon.

1. It causes Lateral Line Disease (Hole in the Head).
2. It outright Kills Zoanthids.

Is there any Proof to those two statements which I hear All the Time?

 

[Randy Holmes-Farley]

I think some types of GAC might do #1, possibly by releasing fine particles. For years I had problems with a yellow tang with a dorsal fin issue that many described as similar to HLLE, and actual HLLE in hippo tangs.

I replaced the Marineland Black Diamond GAC with ROX (which is supposedly acid washed), and at the same time stopped much ozone (only rarely used now). In any case, the yellow tang I have now has never gotten that problem (haven't tried another hippo). Did the GAC change help? Was it ozone? Not sure, but GAC and HLLE issues is, IMO, a reasonable hypothesis for some of the issues folks have.

2. Don't know about zooanthids and GAC, but I have some zooanthids that have been in my tank at least three years and I use ROX GAC 24/7. They are not exactly taking over the tank, but they are holding their own.

 

[SantaMonica]

Wow I did not know that GAC broke chloramines apart. I knew that Vitamin C did.

 

[Mr. D]

I'm interested in the effect on zoanthids.

 

[clownfitch]

I'm interested in the effect on zoanthids.

As am I! I've never heard that but I have been having issues with most if my zoa colonies in one of my tanks for the last 8 months and have tried everything to make them happy again. I'm going to take the carbon offline tonight and see if that has any effect on them over the next few weeks.

 

[Randy Holmes-Farley]

Wow I did not know that GAC broke chloramines apart. I knew that Vitamin C did.

That's a big benefit of the carbon block in an RO/DI.

 

[Aquaph8]

I think some types of GAC might do #1, possibly by releasing fine particles. For years I had problems with a yellow tang with a dorsal fin issue that many described as similar to HLLE, and actual HLLE in hippo tangs.

I replaced the Marineland Black Diamond GAC with ROX (which is supposedly acid washed), and at the same time stopped much ozone (only rarely used now). In any case, the yellow tang I have now has never gotten that problem (haven't tried another hippo). Did the GAC change help? Was it ozone? Not sure, but GAC and HLLE issues is, IMO, a reasonable hypothesis for some of the issues folks have.

2. Don't know about zooanthids and GAC, but I have some zooanthids that have been in my tank at least three years and I use ROX GAC 24/7. They are not exactly taking over the tank, but they are holding their own.

I had the exact same experience with the exact same two fish in my old tank, I also use the Rox carbon now and no more issues. I'm not sure what it was caused by but I did use generic carbon back then so.... Randy did your fish ever get any better looking after the switch?

 

[Randy Holmes-Farley]

I had the exact same experience with the exact same two fish in my old tank, I also use the Rox carbon now and no more issues. I'm not sure what it was caused by but I did use generic carbon back then so.... Randy did your fish ever get any better looking after the switch?

if I recall correctly, I had a tank wipe out while on vacation before I had a chance to see if it was helping or not. After the wipe out, when restarted, the problem has never come back, but they were new fish.

 

[lionfish5740]

In general the list of things bound mostly is organics and whole bacteria that may like to grow on it.

I'm not surprised that bacteria would colonize GAC because they colonize just about everything else. It did make me question how much they participate in saturating it to the point of becoming inert.
For example, I only run GAC periodically for short intervals (< 12hrs per 2-6 weeks) but leave it in the tank water in-between. So do they build up over time and block the GAC to the point that I shouldn't let the reactor stay filled with tank water in-between? Or just use fresh carbon each time?

I realize there are too many variables to be offered an accurate time limit if this is the case.

I'm open to everybody's opinion as well as any expertise

 

[that Reef Guy]

As am I! I've never heard that but I have been having issues with most if my zoa colonies in one of my tanks for the last 8 months and have tried everything to make them happy again. I'm going to take the carbon offline tonight and see if that has any effect on them over the next few weeks.

Let us know how that turns out.

I really want to know if it makes a difference.

 

[Randy Holmes-Farley]

I'm not surprised that bacteria would colonize GAC because they colonize just about everything else. It did make me question how much they participate in saturating it to the point of becoming inert.
For example, I only run GAC periodically for short intervals (< 12hrs per 2-6 weeks) but leave it in the tank water in-between. So do they build up over time and block the GAC to the point that I shouldn't let the reactor stay filled with tank water in-between? Or just use fresh carbon each time?

I realize there are too many variables to be offered an accurate time limit if this is the case.

I'm open to everybody's opinion as well as any expertise

That may be the case, yes. When I was first dosing vinegar, a significant amount of the bacteria apparently grew in the GAC/GFO mixture that I use in a canister, and I rinsed it out once every week or two.

OTOH, bacteria cannot get into many of the pores since they are too small, so it would be more a matter of covering the openings.