Skimmer skimming question

[mvallee]

I bought this Eshopps S-300 Snow Cone Skimmer new about 18 months ago and having a strange issue.
Every 3 weeks I have to clean the skimmer, I mean take it out of the tank, bring it outside and blast it with a hose. For some reason lately the bottom of the skimmer in that time gets sludged up with this thick sludge around 1/4" thick, the skimmer continues to skim but it is a very wet skim not thick and goopy like what builds up on the bottom.

The big problem is when I shut it off and pull it out there is no way to get it out without a good amount of that sludge going back into the tank.

If I had to describe it I would say the bubbles are rising and overflowing the top of the cup but the detritus is dropping back down into the skimmer not quite rising out with the bubbles. The neck of the cup gets a thick goop on it too just like what is on the bottom of the skimmer and the skimmate is green just not thick like I have seen others getting.

Here is a quick video of the skimmer 10 minutes after putting it back in the sump after hosing it out. I have soaked and thoroughly cleaned all the internal workings with a vinegar water solution and had the same result.
To me it looks like every other video I have seen of properly running skimmers.
What would cause this?
[video=youtube;d-1qFjrYZsI]https://www.youtube.com/watch?v=d-1qFjrYZsI[/video]

 

[mvallee]

I should add this is a 180 gallon tank with a 55 gallon sump with probably around 200 pounds of live rock so volume of water wise I would guestimate 150-160. this skimmer is rated for 250-350G. I am also not overstocked, I really can't keep a clean up crew thanks to my green bird wrasse pair but as you can see most of my tangs are still small to mid sized.
Here is a quick video of my stocking and tank setup

[video=youtube;LMj3AQ2Vztc]https://www.youtube.com/watch?v=LMj3AQ2Vztc[/video]

 

[delta]

Have you tried drier skimming? to see if that reduces it. that would be my first step to trouble shooting it.

 

[mitant]

Check that the water level in your sump matches what the skimmer needs. Some skimmers have a tight tolerance of operating conditions, some auto-adjust, some don't.

 

[delta]

after watching the video again I would also look at where the skimmer is in your sump. It should be in the same chamber with the tank drain. SO it gets raw tank water before Dissolved organics start to separate out. This will increase the skimmer ability to remove the Dissolved organics. In the video it looks as if it is in a different chamber with baffle in between. What could be happening is the organic going into the skimmer have already dropped out of solution. Three factor in skimming the Surface area being skimmed properly/efficiently in the display tank, The placement of the skimmer to ensure raw tank water is being skimmed and the balance of tank/sump turn over to Skimmer processing.

 

[wpeterson]

Are you running filter socks or other mechanical filtration prior to the skimmer? Perhaps this sludge is particulate organic matter in the water column that's too large to be skimmed out, so it's settling in the skimmer. The skimmer will be best for the smaller dissolved organic matter.

In our sump, our drain chamber has a large filter sock the water flows through before entering the skimmer chamber. I get a ton of sludgey buildup at the top of the skimmer neck and collection cup, but not in the base. This seems odd.

Alternately, how often are you cleaning the neck/cup? Perhaps cleaning those once a week might prevent sludge buildup if what you have is sludge buildingup at the neck and dropping down.

 

[mvallee]

Thanks for the ideas and suggestions
I do not use filter socks, I have tried a few times but in the layout of my sump and the equipment I have in there it became very painful and when I read many run sockless I gave it a shot and seemed ok just a little more sump maintenance, I agree I need to redo my sump so I can have my skimmer in the first section and everything more accessible, just such a waste of space in the current config.
I keep threatening a basement sump and this could be the kick in the pants i needed to get that started.
For now I am going to raise the skimmer to see if I can get a drier skim and keep the neck of the skimmer cleaner. would be embarrassing if it was the sludge that builds up on the collector cup neck falling back in, it should make it up and over but if it just requires multiple weekly cleaning I can live with that.

 

[JohnK]

Do you carbon dose at all? Could the sludge be a bacterial mat/growth?

 

[mvallee]

I just started cabon dosing less than two weeks and this has been going on for a while.
Hopefully if I can get the skimmer straightened out I will not need to anymore. not sure what bacterial mat/growth would look like (google was not much help either) but this looks like the stuff that builds up in the bottom of the sump over time, brown and slimy.