Dirty cup=no skim?

[rustyjames]

I have a 9002 and seems that after 3 days or so there is a nice collar of foam at the top of the cup and about 1/4" light brown liquid at the bottom but foam production stops unless I crank the blue screw way open. If I don't touch the screw and just clean the cup seems to work again. Is this normal? Do I just need to clean the cup out every-other day?

 

[railroader46]

I have a 9002 nad every other day I use the tapered brush and clean the skimmer neck.

 

[rvitko]

Yes, this applies to any skimmer, the deposits on the cup contain fats and oils that break down the foam so it doesn't collect in the cup. You can get a longer between cleaning time by setting it to skim wetter. But any skimmer will work best if the cup is cleaned daily.