MACNA Lecture - Organic Carbon Dosing

[rlpardue]

I attended Hans Balling's lecture on Organic Carbon Dosing ("OCD") and have some questions regarding some of his points.

He mentioned that OCD may in fact benefit certain non-bacteria organisms in our corals such as fungi and "protists" (I think that was what he said, his German accent is pleasant but difficult to understand at times). This was the first mention I've read about the effects of OCD on any organism other than bacteria colonies, and it may help to answer some questions raised by the article in Advanced Aquarist ("AA") on OCD, protein skimmers, and bacteria. Is this a completely new finding? (Balling's mention of non-bacteria organisms benefiting from OCD). Has anyone found any interesting research on the subject?

 

[DHyslop]

There's been a lot of talk that it might benefit non-photosynthetic critters in our tanks. Many have observed rapid sponge growth, but I don't know if anyone has done a real experiment.

 

[bertoni]

Anything that consumes bacteria might benefit. Sponges and protists are two possibilities.

 

[disc1]

I haven't read anything on the subject but I certainly wouldn't be surprised to learn that there are other things in our tanks that can benefit from organic carbon in the water. It is certainly an unnatural state, but I see no reason it couldn't happen. Your body will burn ethanol for energy, so why wouldn't anything else. Especially if the doses get high. I'm not saying that it happens or not, but I certainly would not find it too surprising.

My next question would be whether or not it makes a difference with the concentrations you build up, for example single big dose vs. spread out dosing. I wonder if the bacteria or something else can out-compete for the available ethanol.

 

[jgsteven]

I put a biopellet reactor on my tank about 8 months ago. Since then the small fanworms previously in the tank have been reproducing at an extraordinary rate! My guess is that its related to the pellets (or something that eats the carbon in the pellets).

...of course they gave me cyano too, but thats a different story...

 

[rlpardue]

Disc1, your second question is a good one to consider. I'm merely a simple caveman lawyer (SNL reference), not a chemist, but at MACNA Dr. Balling suggested dosing the carbon-containing substance (e.g., vodka or vinegar, etc) once or twice daily rather than in small amounts throughout the day. The rationale for such a method has to do with measured levels of carbon on ocean reefs throughtout the day. The level apparently spikes rapidly during the daytime, then rapidly declines. He suggested that dosing in small increments (as with a dosing pump) would allow other organisms to out-compete the organisms we are trying to grow.
DISCLAIMER - I'm a simple man, not a chemist, and the above conclusions are paraphrased from a lecture given by a non-native-English speaker with a thick accent. Do not rely on my paraphrase without obtaining independent confirmation of the conclusions.