Not to sound harsh but I'd buy a new skimmer.
It took me 2 years to finally get my sump going but now that I have it going and the new skimmer up and going, it's an AquaC MR2, I'd never go back to a HOB skimmer. The ammount it skims versus the CPR is unbelievable.
My CPR constantly needed tweaking and it was more of a headache. I spent like 180 bucks on the MR2 buying it used off someone and I spent close to 70 bucks for the CPR. For 110 bucks more it does a way better job then that HOB could ever dream of doing.
But if you don't have the bubble baffle for your CPR you can try putting in some macro algae in the second chamber to see if that helps but be careful what kind macro algae you put in there.
I had the same problem as you and I even had the baffle for the bakpak.