Skimmers Good or Bad or Both

[Zero Nitrates]

I am setting up a new system. 120 gallon with a 300 gallon livestock trough for a sump. Right now there is only saltwater in the system. No rock or fish. The skimmer I have is a Reef Octopus SRO external 3000. I started the system up to check for leaks and make sure the return pump is running correctly and the skimmer is running correctly. Since it is up and running I decided to cycle the tank somewhat with some bacteria.

The skimmer was pulling nothing out of the water until I added bacteria, then it pulled out just about all of the bacteria out of the water and now afterwards it is pulling nothing out of the water.

So my question is Are skimmers good, bad or both for our reefs?

The only time I have noticed skimmers on my other systems pulling anything out is when I clean my glass. I am assuming that it is skimming the algae from the glass.

 

[dacianb]

skimmers pull out if there is something in the water; you have nothing, so nothing to pull.
Those bacterias are seeds (theoretically) and you need something for them to settle (rocks?). Bacteria density in water column is much lower than at rock/sand level.
You should not spend your money on bacteria without rocks. Add some nasty live rocks and the skimmer will work hard for days to clean up the water

In my opinion are good for tanks (better safe than sorry) - skimmers took out excess organics.

 

[Zero Nitrates]

What about bacteria in the water column?

 

[den75]

What about bacteria in the water column?

When your tank is cycled most if not all of your biological bacteria is on the rocks. Virtually none is in the water column. When you put the bottle of bacteria in it didn't yet settle or get a chance to establish itself in the rocks so the skimmer removed it. Probably should have left the skimmer off a good 24 hours or so after you added the bacteria.

 

[dacianb]

What about bacteria in the water column?

those are neglectable (have them or have them not doesnt make a difference). They need hard, porous surface to settle and start working.
And dont worry, no skimmer can pull out all bacterias from water. Actually skimmers pull large organic molecules which bond to air bubbles. Bacterias, dissolved minerals, etc are safe.
UV can kill bacterias and a big UV unit can sterilize the water in tank.

 

[dacianb]

When your tank is cycled most if not all of your biological bacteria is on the rocks. Virtually none is in the water column. When you put the bottle of bacteria in it didn't yet settle or get a chance to establish itself in the rocks so the skimmer removed it. Probably should have left the skimmer off a good 24 hours or so after you added the bacteria.

seems that there are no rocks in tank. Just water, bacterias and skimmer.

 

[den75]

seems that there are no rocks in tank. Just water, bacterias and skimmer.

Well, adding the bacteria at that point then was pretty much useless.

 

[Zero Nitrates]

Doesn't Carbon dosing target the bacteria in the water column?

 

[dacianb]

Doesn't Carbon dosing target the bacteria in the water column?

nope. Target some denitrifying bacterias on rocks (and in rocks), but also encourage growth of free floating micro-algaes which are indeed removed by skimmer. It is same with having an algae scrubber and clean it from time to time. But with vodka algaes are very very small and the skimmer do your job. This algaes, next to carbon consume NO3 and PO4 from water.
But there is a big difference between bacterias and algaes. all are tiny jerks, I know, but do different things.

 

[Randy Holmes-Farley Verified Community Expert]

The skimmer was pulling nothing out of the water until I added bacteria, then it pulled out just about all of the bacteria out of the water and now afterwards it is pulling nothing out of the water.
s.

Why do you think it removed "just about all" of the bacteria you added?

I don't really think there is that much downside to skimmers (mostly expense) and there are several clear benefits.

 

[Zero Nitrates]

Randy, I am wondering if it is good to run a skimmer and have bacteria counts 3 times less than a reef in the ocean. Skimmers pull a good bit of TOC out of the water. Seems like the good and bad equals out.

 

[Randy Holmes-Farley Verified Community Expert]

It's possible the bacteria reduction is a downside, but removal of whole bacteria may also be a benefit in terms of nutrient export and possibly diseases involving bacteria, and if driving bacterial growth with organic carbon, the downside might be partly offset.

 

[Zero Nitrates]

Thanks Randy!

 

[Randy Holmes-Farley Verified Community Expert]

You're welcome.

Happy Reefing.

 

[Zero Nitrates]

Could running your skimmer for a period of 6 hours a day instead of 24 hours a day solve some of the problem? Of course this would depend on the bioload of the system.

 

[Randy Holmes-Farley Verified Community Expert]

Could running your skimmer for a period of 6 hours a day instead of 24 hours a day solve some of the problem? Of course this would depend on the bioload of the system.

Which problem?

 

[Zero Nitrates]

Skimming out to much bacteria

 

[Randy Holmes-Farley Verified Community Expert]

Skimming out to much bacteria

Maybe. But all of its positive effects will be lessened too. I'm not sure which effect would be more important.

OTOH, you can increase bacteria with organic carbon dosing.