Berlin Hang-on Skimmer not skimming, help!

[AnotherGoldenTeapot]

Sounds like your pump is not sufficently powerful.

 

[DreamMarine]

I just purchased a used berlin skimmer with a new rio 2500 pump. I set it up last night in my tank but there is still no foam in the cup. I have my old modified sea clone still running in the tank and it's skimming just fine. Would there be a new break in period with a used skimmer? The air adjuster is all the way out, do I need to adjust it?
Thanks for any help!

 

[DreamMarine]

I'm using a RIO 2500 which was the recommended pump?