Check to see if your air silencer is clear. When you blew through the air intake hose, did you also blow through the silencer portion?
If that path is clear, and there are no kinks/restrictions in the air inlet tubing...this sounds odd...but you can try unscrewing the pump from the skimmer...like you were removing the impeller for cleaning, and then re-tighten it again gently....do not overtighten. For some reason, the first few months I had my Coralife 65 it would do exactly what you described. I would take the pump apart and put it back together a few times and all of a sudden it would start working again....I never found out why.
One mod I did to that skimmer that actually did anything, was drill out (by hand) the nipple where the air intake hose goes, big enough so a piece of rigid airline tubing fit in snug. I crazy glued a 2 inch length of the rigid tubing, and connected a larger diameter air hose to it. In my case, it made the skimmer perform better.
Cheers