skimming organic carbons

[chrisjames]

I’ve been testing vodka’s ability to boost heterotrophic aerobic bacteria and therefore reduce nutrients in a spare empty tank filled with 35ppt salt mix. Basically I add ammonium chloride and then vodka until I get a nice cloudy broth and sure enough the nutrients crash. The problem I have is coming up with a method to remove the bacterial bio mass so that I can reliably export these nutrients. Low micron filters can’t grab the bacteria and skimming also fails to clear the water column of them. I’m now thinking that if I could find a more hydrophobic form of organic carbon then the bacteria might better "stick to it" and skim out more effectively. You mentioned in your article “what is skimming” that acetone was mind way between hydrophobic and hydrophilic. Would this be a better choice? What other organic carbon could I consider that would feed the bacteria and also get trapped at the air/water interface in the skimmer?

Many thanks

[marsh]

It is my understanding that aggressive skimming does help. The threads which deal with carbon source addition (ethanol, sucrose, glucose, acetate, etc) report large increases in skimmer output following the carbon source addition.

[Boomer]

Have you tried using large amounts of GAC ?

[chrisjames]

I also thought that aggressive skimming would work but I don't think this is the way the bacteria is removed from zeo type set ups. I think SPS corals play a far bigger part in bacteria assimilation because I’ve tried skimming it out with some highly regarded skimmers and it's not happening. May be you also need some organics present that helps to bind the bacteria in some way and because of the way I’ve set the test up I have no livestock producing organics. I’ve got some organics I could add I might try that.

I haven't tried carbon as I was trying to come up with a system that needed the fewest possible additions. Thinking about it boomer, would GAC trap the actual vodka because if so this might localize the bacterial growth and that might be useful.

[Boomer]

Bacteria love living inside GAC.

Vodka ? It should it is mostly ethanol. Even if it was not hydrophobic the molecules would still get trapped in the pore structure of GAC.

Coral feed off of bacteria and bacteria are also going to collect on the mucus which they shed-off. Organics do help them bind better.

In the zeo types the film is either manually removed or the media is replaced.

[Mike O'Brien]

I think that is where shaking the media a few times a day comes in. By that time there is a bacterial / detrital mulm that can be removed by the skimmer more easily than just free floating bacteria.

IIRC it's the Hyatt method that uses large ammounts of GAC.