Red Slime and Carbon

[Tbduval]

Just got done reading the post Highlandreefer posted about DOC and carbon. http://reefcentral.com/forums/showthread.php?t=1943092 It got me thinking about my tank.

First, I don't run carbon on a normal bases. Actually, I really never run it. Then I decided to buy some ROX 0.8 from BRS. First it is the best carbon I have ever used. Little dust. I didn't notice that big of change in water clarity.

So I have been battling a little red slime(green in my case) and decided to go heavy on the carbon and GFO. I always run GFO in my tank. About a day or 2 after I added the carbon, I noticed the slime is on retreat! :fun2:

It lead me to why is on retreat? Is it really the DOC's? Is the carbon taking away a good food source? How long until I change the carbon out? Should I really run carbon 24/7? It seems like I should!

Just wanted to hear some opinions!

Thanks!

 

[Humu Humu]

I read that thread too, and taking into consideration the graph that shows the DOC jumping right back up when carbon is removed, it seems that it should be run all the time.

Not sure but that's what I got out of the article.

 

[Tbduval]

Agree. It most likely should be ran 24/7 from this past experience. I think Boomer said it was more of the bacteria that grows on the carbon keeping the DOC's down, more than the carbon doing it job. It was most likely already exhausted but the bacteria was helping with DOC's.

 

[bertoni]

The carbon will act as a biological filter if it's left in the tank a while. To reduce green slime, it likely is adsorbing organic compounds, in my best guess. Otherwise, it's the same as live rock or maybe bio-balls.

 

[mesocosm]

Greetings All !

... Is it really the DOC's? ...

Nope ... cyanobacteria are NOT carbon limited so a downward shift in DOC concentration in the water column (or within their microclimate) doesn't have a significant impact on their growth. They're photosynthetic ... they can access inorganic carbon sources to meet all their needs. Some strains do have the capacity to exploit DOC and as a result can get a growth boost from DOC, but you're never going to crash a cyanobacteria population by starving them of DOC.

... Is it really the DOC's? ...

Nope ... cyanobacteria are nitrogen and phosphorous limited. There's no better way to safely crash a cyanobacteria population than to starve it of either N or P sources. Boomer is indeed correct ... no surprise there ... it's the biofilm on the surface of GAC that's consuming N and P that "out competes" the cyanobacteria for available N and P nutrients.

BTW ... GAC (granulated activated carbon) has a long history as a bacterial growth media in aquaculture. If you go back through the literature of the 1940s through the early 1960s you'll find that GAC was a preferred bioreactor media for the control of N compounds. It was abandoned because of its relatively high cost, the speed at which its pores became clogged, and the labor costs resulting from having to remove the excessive biofilm growth that disrupted the bioreactor's filtration efficiency.


HTH
:thumbsup:

 

[jimnrose]

Gary, thanks for your inputs. Cyanobacteria is a real bear for us newbies.
Happy Holidays, Jim