Skimmer gunk

[lmetcalf]

Hello all,
Im a first timer with a protein skimmer. I just got one yesterday and set it up. Its one of the ones where you have to adjust the airflow, so im trying to get it just right.

What is the stuff in the collection cup supposed to look like? I was expecting frothy brown bubbles. What i have is brown liquid.

Is this how it's supposed to be?

[abrahamavelar]

green or brown it has to brake in first mine took 2 days before it collected something beside just water and now it only collects gunk just give it some time and u will see some green or brown thing