Is Carbon an SPS Coral Killer?

The effects of prolonged carbon use on marine fish have recently been well documented, but the same cannot be said for corals, particularly SPS corals according to Leng Sy of EcoSystem Aquarium. Recently Leng added 2 liters of high-grade German carbon to his experimental 550 gallon, SPS-dominated reef aquarium. In short time, he began to see bleaching on many of his SPS corals shown below. Leng believes this was due to the removal of essential trace elements by the activated carbon he introduced. He has since removed the carbon and completed a 250 gallon water change and has reported that the corals are beginning to rebound. What do you think of Leng's theory?

Activated carbon has been used for years and is very popular to use in both freshwater and marine aquaria due to its effect at making aquarium water look sparkling clear. The effect of activated carbon on marine fish in aquaria is well known. Heavy use of activated carbon over prolonged periods of time can lead to the development of hole in the head disease, also called lateral line erosion in fishes. This effect is commonly seen in tangs and angelfish, but can even be seen in damselfish when carbon is used continuously over a long period of time. However, the effect of activated carbon on corals is not well documented in reef aquaria. It is our experience that the heavy use of activated carbon in reef aquarium can kill corals. This effect will show when otherwise healthy corals suddenly start bleaching from the tips. Watch this video.

You can also follow us in our blog Blog | EcoSystem Aquarium. There are also other ongoing experiments that you can follow here as well.


Thanks,
Leng Sy
President/CEO
EcoSystem Aquarium

 

IMHO, his hypothesis is wrong. The bleaching could very well and more likely be attributed to the vast increase in PAR due to the rapid improvement in water clarity. So much for stability.

 

Interesting point Greg!

 

His carbon removed sooo many trace elements it was starting to kill the coral?
I suppose it's possible.

This guy is the water change master.

 

That, and a sudden drop in dissolved organics. A double-edge sword.

 

Never knew prolonged use of carbon could contribute to HOH and lateral line erosion. What is the standard practice with carbon then month on month off?

 

I think you can use everything in moderation. I use just enough carbon to remove any chemical warfare that might happen in my tank from corals being territorial. But for removal of organics, I use a skimmer, so it's a slightly different application than this.

 

I use 250ml Seagel for a 46gallon tank would that me considered too much? ITs a mixture of carbon and phosguard

 

I use carbon and I have sps and have seen nothing like this happen.

 

Activated carbon affirmed as causative agent for HLLE disease — Advanced Aquarist | Aquarist Magazine and Blog

Activated carbon indicted in inducing head and lateral line erosion — Advanced Aquarist | Aquarist Magazine and Blog

Some people either don't use it at all anymore or feed the carbon filtered water through a 5 micron sock to remove carbon particulates. Most don't even seem to know about the link. I don't use carbon.

Now the carbon and coral issue. As far as long term effects, I believe them to be minimal. Carbon likely does bind up some trace elements, but due to the chemical nature of most activated carbon and the great quantity of polar organic molecules in our aquaria, few trace elements are likely lost. Your skimmer likely removes more trace elements than carbon, Feature Article: Elemental Analysis of Skimmate: What Does a Protein Skimmer Actually Remove from Aquarium Water? — Advanced Aquarist | Aquarist Magazine and Blog. As far as I can see, no one has done a study on what carbon removes. Maybe a new article idea for Randy?

As noted before, it was more likely due to water clarity, as this has been well documented when adding large amounts of aggressive carbon, i.e. Rox 0.8, to a system. With the increase in PAR due to fewer organics(tannins and humins notably), photosynthesis increases, oxygen radicals build up in the tissues, and burnt tipped corals are the result. pH is likely also shifting with the increase in clarity. With increased photosynthesis, more CO2(carbonic acid) is absorbed and O2 is released. Then, with the reduction of tannic and humic acid(they are what turn your water yellow) the pH further increases. pH swings are also well known for causing burnt tipped corals.

There is yet even another potential hypothesis, contamination. What is potentially in this "high quality German carbon"? Could it have been a bad batch and it leached heavy metals into the aquarium? This has/does happen. No analysis was made before or after the carbon was used to see what was in it and what was removed.

Without a much, much more controlled experiment with carefully analyzed results, this is all conjecture.