Did you know that the main feature of the skimmer is not to lower nutrients?

[kharmaguru]

If you'd followed up on the roles of sponges in reef ecosystems you'd know you already have them. As DOC is their food source they will have already grown to match the amount of food available. As they are removing DOC 1000X faster than teh bacterioplankton your skimmers are removing you don't need much.

Just to be devil's advocate, if the sponges already in my mature system ( it's moved around but I have rock that's been in my system for 20+ yrs, and the rock in my sump is covered in sponge) remove DOC at 1000x rate, why even care about the presence of a skimmer? It seems the sponges don't.

 

[Paul B]

I wonder what my skimmer is removing?
Looks appetizing. I put it on Cappuccino.

 

[Paul B]

This is an interesting discussion and to tell the truth I have been using a skimmer since Sanders came out with the thing in the early 70s and I still use one. I always built them myself and never thought to run my reef without one. But for an experiment, I may turn it off for a few weeks and see what happens.

My venturi skimmer is 5' tall and I normally run 50mg/hr Ozone through it just for fun.

 

[Timfish]

Just to be devil's advocate, if the sponges already in my mature system ( it's moved around but I have rock that's been in my system for 20+ yrs, and the rock in my sump is covered in sponge) remove DOC at 1000x rate, why even care about the presence of a skimmer? It seems the sponges don't.

Because you are still altering the microbiomes. Look at Feldman's research, unskimmed systems have microbial counts in line with wild reefs. Skimmed systems are way off.

 

[Timfish]

This is an interesting discussion and to tell the truth I have been using a skimmer since Sanders came out with the thing in the early 70s and I still use one. I always built them myself and never thought to run my reef without one. But for an experiment, I may turn it off for a few weeks and see what happens.

My venturi skimmer is 5' tall and I normally run 50mg/hr Ozone through it just for fun.

So how much of that yucky skimmate is actually cultured in the skimmer? One thing that has seemed incongruous to me is the presence of lots of anaerobic stuff in skimmers but no anaerobic pockets in systems when I move them.

One thing I'm intrigued by is your use of tidepool muck periodicly. Now that we can test for different microbial stuff a long term study of what happens to tank microbiomes whith wild microbes added versus not being added I think would be enlightning.

Your periodic use of diatom filter is another factor that I think plays into keeping healthy microbiome and I think deserves more attention. We know corals manipilate the microbial stuff in the water around them and shed their mucus layers as they age to renew the microbial stuff living in the mucus layers. Unlike skimmers which can't touch anything hydrophllic, diatom filters will remove everything above a certain size (1 micron?). Since both coral DOC and algae DOC can promote excessive bacterial growth that can be harmful (in particluar algae DOC promotes pathogenic shifts) periodicly reducing everything with a diatom filter may more closely mimic processes on reefs. (I've seen corals that have turned brown with out any change in maintenance or lighting return to normal coloration with just running a diatom filter a couple hours.)



Besides all the sponges you have

 

[Paul B]

I don't know why in the last 2 weeks or so the skimate is so thick. It doesn't liquify and stays a thick foam forever it seems.

I had to let it "blob" into a bucket. I am glad whatever it is the skimmer is removing it but in the long lifespan of this tank, this has never happened.
Fish and most corals seem fine. One large duncan hasn't opened in a couple of weeks and I don't know what that is about. Since I eliminated the sponge the water chemistry has been all screwed up.

 

[Timfish]

I don't know why in the last 2 weeks or so the skimate is so thick. It doesn't liquify and stays a thick foam forever it seems.

I had to let it "blob" into a bucket. I am glad whatever it is the skimmer is removing it but in the long lifespan of this tank, this has never happened.
Fish and most corals seem fine. One large duncan hasn't opened in a couple of weeks and I don't know what that is about. Since I eliminated the sponge the water chemistry has been all screwed up.

I'd worry about what's being left behind since skimmers don't affect hydrophillic stuff like sponges do. It's fascinating what their finding sponges are messing with in reef systems. To reitterate or expound on some of your comments it seems as reef aquarists much of what we have accepted about carbon, nitrogen an phosphorus cycles is far too simplistic to adequitely understand the how they affect the microbial processes in reef systems.

 

[Paul B]

The health of the livestock seems normal even though the skimate looks like volcanic fallout. I have also been running a "Poly Filter" while this skimate looks like this because as you said, I have no idea what else is in my water after I eliminated the sponge.

 

[Timfish]

Have you tried running your diatom filter since you removed your sponge?