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Bill's MACNA Logs - Dissolved Organic Carbon (DOC's)

So thanks to the efforts of so many great people, myself and many others had the opportunity to bask in the collective wisdom of some of the greatest marine aquarists and scientists alive today!

So what did I learn? Well, I went to all but one speaker session and want to share what I heard, mostly so I can come back here and read it as it starts to seep out the gaps in my brain. ;D

But first a warning to noobs and reefers I may have debated with in the past! With the exception of switching all lighting to VHO's, I have statements from real life reef professionals backing up most of what I practice with my own tanks, so I won't go quietly into the night. ;)

So lets start with a topic that is sure to generate a lot of creative discussions, dissolved organic carbon.

Ken Feldman a reef aquarist and professor of chemistry at Penn State is doing some great work on DOC's and in particular, working on methods of quantifying skimmer performance.


Here are some of the key points that I took away:

1) Not all DOC's are capable of being removed by skimming, probably less then half.
2) 2/3 of the material removed by a skimmer isn't even organic
3) GAC, granulated activated carbon, can remove more DOC's than skimming.
4) All skimmers perform about the same at removing dissolved organic carbon.
5) Proper biological filtration and water changes have the greatest impact on reducing the level of DOCs.
6) Spikes in DOC after feeding are quickly removed with good biological filtration.

So let me see..... ::) Do we know anyone who uses cheap, undersized skimmers; feeds heavily; runs carbon 24x7 and likes to do weekly water changes??

I will add that Bob Fenner does not see a lot of benefit in continuous carbon use.

Let the creative exchange of ideas now begin! :eek:
 
this is awesome - thanks for sharing bill.

I assume when we talk about using GAC - it's thru a media reactor versus just a bag in the sump?
 
I'll chime in here Bill.

Most proponents (sp?) of GAC recomend active (reactor) vs passive (bag somewhere in the sump).

My understanding is while both can work, proper use of a reactor to actively pass the water over the carbon is far more effective then passive use by just placing a bag somewhere in the water flow of the sump.
 
reeferwanabe said:
So, other than our live rock. what is the best biological filter?

A healthy sand bed and fuge are two possible answers. But there are others, algal scrubbers, aptaisia scrubbers there are a few possibilities that have ben put to use. All have costs and rewards.

Bill, gotta run at the moment, but this is a great topic...

.... I'll be back!
 
FWIW-

I personally do not use a skimmer.

I use three passive media bags of GAC changing one bag weekly (FIFO).

I am successfully keeping all types of corals, and my nitrates usually hover at about 10.
 
Lots of stuff going on at home today, so sorry if the answers are quick.

In general reactors work better than passive, but something is better than nothing.

Ed, I love the Warner Marine reactor so far. Easy to change and adjust and great flow through the media.

Bax, we all know I love sandbeds and a fuge is also a great thing to have. I'll be adding another 50lbs of rock to the fuge zone of my sump as soon as it is cured.
 
Don't forget that the color of your skimate has nothing to do with how much TOC is being removed.

In Feldman's test (admitadly preliminary) showed that there was actually an inverse curve to the cost of the skimmer and the efficiancy. I.E. the Bubble Kings werethe worst performers while the PM air stone skimmer was most effective.

Interesting stuff, but I'm not ready to throw out my ETSS just yet and Feldman isn't recommending it either. His point was that skimmers are useful but they're just not as effective as we thought.
 
Guess it makes sense as in nature you have skimmers(waves), rock, sand, algae, and others. I am of course in the sand bed group and I pride myself in my fuge so I am biased. Looking forward to all the discussions, because unfortunately I missed most all the demonstrations and lectures, darn 3 year old and wife. :D
 
Wow, can't believe I missed this presentation at Macna. Sounds really interesting.

blange3 said:
Ken Feldman a reef aquarist and professor of chemistry at Penn State is doing some great work on DOC's and in particular, working on methods of quantifying skimmer performance.

Would the above statement suggest that the amount of skimmate that a skimmer produces isn't a good measure of a skimmer's effectiveness? I'm not talking about really wet skimming practices, but the thick sludge of stuff that comes out by those who skim dry.

Since he already stated that most skimmers perform about the same, how is he measuring this?

Did he say anything about what skimmate is composed of, if less than half is DOC?
 
Great topic Bill but since i didn't get to this one i'll have to go along for the ride. One thing i'm glad to hear i don't have to go get a new skimmer.
While i have no quantitative eveidence, my thought would be GAC is a benifit. As it has been mentioned you will need to change it often
 
He did break down the inorganic part, but I didn't take notes. A lot of it was related to the skeletons of things like diatoms.

The two plus points were removal of phosphates and silica; although most of that was probably related to the diatioms. Hopefully he'll offer up his presentation for posting or my memory will improve. I know various carbonate compounds were involved.

It was preliminary work, but as Jeff it does seem to indicate that skimming is useful, but not the most important element of controlling DOCs.
 
I know Jeff really needed to think about that one. Check it out

3969999137_8310c8298f.jpg
 
I've been running ozone for about 4 months and the skimmer does not pull anything any more. It's just a place to run the ozone thru.
Has anyone ever experimented with a fluidized bed filter? Always been interested but never gave it a try. I heard most of the ones that fit under the tank are good for bacteria but you need a taller version for nitrate removal.
 

Daniel

Officer Emeritus
Officer Emeritus
Edward771 said:
How is that Media reactor from WM Bill? I never got a chance to go back over there to buy one.
Ed give Jon a call at WM. He will help you out. I have had mine for 8 months and love the plug and go of it.
 
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