Skimmate gone...

So, my skimmate is gone. I've been trying to diagnose the problem and I've come to the conclusion that there is no problem, just nothing to skim.

I've been skimming some dark, nasty skimmate for the past couple of months, but for the past couple of days it has pulled nada. My skimmer is a bubble magnus nac 3.5 running on a 54g bow front with a 15g sump. The bubbles are tiny and a lot less dense than before. I pulled my skimmer out, cleaned the pump and checked everything twice. Nothing is wrong. The skimmer sounds like it's pulling good air and the pump is moving its regular amount of water.

The culprit. I think the cause of the reduction in skimmate is due to the addition of carbon and GFO. I added BRS premium Rox 0.8 carbon and BRS high capacity GFO. Is the addition of the carbon the reason for the dramatic decrease in skimmate? I'm curious to see if others have had the same experiences so that I can stop worrying about my skimmer. I'm prepared to replace the atman pump with needle wheel impeller if necessary, but I thought I'd ask you all first. What do you think the problems is, if any?

 

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when is the last time you cleaned your skimmer?

 

I say its the carbon and gfo. Im sure when the get full your skimmer will pull more. Check your salinity...low salt will cause less dense bubbles and the skimmer should have a constant 6-8 inches of water (if its a bubble magus)....less water less skim.

 

Most likely the carbon and GFO are the cause. Make sure and clean your venturi valve expecially where the air intake is to remove salt build up.

 

I would blame it more on the GFO than carbon. I run carbon on all of my tanks and still pull nice dark skimmate daily.

 

Not sure what you mean by cleaned... I took the skimmer out yesterday, checked all air passages for salt creep, dumped out a little gunk that had collected in the bottom, took the pump fully apart to clean and check for any interference with the needle wheel and reassembled. I did not clean the body of the skimmer though. There is a thin coat of coralline algae on the inside of the skimmer. This hasn't interfered with performance before, do you all think it should be removed?

 

That was my first thought, I checked the air line, the Venturi intake, etc... Everything was shipshape. No salt buildup to my surprise, but I cleaned it while I had it out just for good measure.

 

I checked my salinity with my new fan dangled refractometer from BRS and it's showing my specific gravity to be 1.024, a little low. This may be one of the factors adding the the low skimmate issue.

 

Yes, many, myself included have experienced this. Heck, I know to change out my GAC if my skimmer starts working better all of a sudden. Also, recently, there has been some research and it is being shown that GAC is generally much more effective at removing organics that skimming, but has limited capacity. So, really no surprise at all. The benefit of skimming, in my opinion, is that it saves you from having to replace GAC as often, and should remove some organic that GAC won't. They do overlap a lot though and GAC is probably more effective when they do.