I got this skimmer: CPR BAK-PAK 2R , Reef Ready. I'm getting good foam in the chamber and a nice return. But the collection cup keeps overflowing. It just keeps slowly filling up until the top starts to rattle and then trickle. Not sure what to do to stop this as there only seems to be one way in or out of the collection cup.

See my post on your other thread... raise the cup using the o-ring, run it dry for a while. Things will break in and get better.

Dave

you could also drill the collection cup and drain it into a larger container