Ah crap, I just noticed the box for the pump says "Sedra 5000." Am I overpowering the skimmer with this pump?
Boy am I observant
That could explain a lot...
Next question (Maybe a moot point, now, but, I'll ask anyhow..) Does the skimmer
have to sit in no more than 4" - 6" of water? I run a high sump volume and the skimmer is too tall to be raised high enough before it hits the top of the tank stand. To lower the sump level would involve taking out baffles and putting in smaller ones and that's ... well ... an awful lot of work.
Do I need to return the pump for something smaller (2500 or 3500)?
Can I throttle the pump back? A valve on the output perhaps?
Plug and play ... pfffffffffffft!!!!

Noooooo such thing!!!