I will disagree with Mark. You are fine.

I have that same little bubble on my pump, a 2 speed SuperPump and it has been running that way for 8 years. There's a curve in the top of the clear cover that catches air and can't purge it. As long as it's just that little bubble in the cover you have no problem. You CAN try loosening the cover slightly to try to get some of the air out but I wouldn't bother.

If it's REALLY sucking air, it will look like a tornado that doesn't quit and be very noisy. Usually that means it's sucking the skimmer too hard and pulling in air. I keep a ball-valve quick connect on my skimmer that I can close down a little if that happens.