Skimmer foams, but won't overflow into cup?

My skimmer (a big, but older, in-sump model from CPR) foams but the foam just sorta gets trapped between the inlet tube and the collection cup cover and doesn't foam over. I wouldn't really characterize the foam as dense, it seems to lack any "push" to squeeze itself into the cup. Its also very white, though after a day the residue in the tube seems to be yellowish.

The pump is a brand new generic maxi jet 1200 clone with a venturi.

Any ideas? Waterline can't get much higher than it is presently.

 

Is the tank setup new? Have you put any red slime remover in? Some in sump skimmers take a month or two to get going.

 

If you put a ball valve on the skimmer's output you would be able to adjust/tune the level of the foam up to where you need it. Also, restricting the amount of air input into the venturi intake will raise your foam level.

 

Also, I've noticed that my skimmer foam production drops when I feed my mysis or arcti-pods

 

Yes the tank is new, about a month or so - 75g, with 75lb of rock and 80lb of sand straight out of an established tank. Cycled fast and now at 0/0/20 (amm/nitrite/nitrate) with 4 chromises and two clowns (in the last week or so).

I expected there to be more action in the skimmer. I overfed once or twice looking to see if the chemistry spiked (to know if the cycle was real or not) and the skimmer stops foaming right when I feed and then goes back to "normal" (i.e. not quite working) in an hour or so.

Dunno if this is all normal or what.

 

Its not that kind of skimmer, technically my sump is a wet dry without any media. The skimmer is designed to sit in the wet dry and the height of the gate that pours into the media chamber is what sets the skimmer water level. I have the gate as high as it will go. The foam definitely reaches the end of the pipe, and beyond, but it just hits the cover on the cup and stays there, no overflowing into the cup.

 

I know what you mean. Sounds like maybe very dry skimming. It will eventually flow into the cup when it foams up enough, but usually ends up depositing loads of brown gunk on the cup lid and in the neck of the skimmer. So try skimming slightly wetter and so how that goes