sj,
It seems that while you may have some air leakage, you may also have some restriction that is greatly reducing flow making it difficult to clear the air from your pump basket. I would definitley clean the filter as soon as possible, I'd also open the pump basket to look for any blockage in the impeller (after disconnecting the power of course). I'd then clean the O-ring and its mating surfaces really well and inspect for any damage (scratches etc.) before putting it back together.